Logic gate and Jim Cramer: Difference between pages

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[[Image:Mad Money with Jim Cramer logo.jpg|thumb|250px|Mad Money logo]]
A '''logic gate''' is an arrangement of controlled [[switch]]es used to calculate operations using [[Boolean logic]] in [[digital circuit]]s. They are primarily implemented [[electronics|electronically]] (using [[diode]]s, [[transistor]]s) but can also be constructed using electromagnetic [[relay]]s, [[fluidic logic|fluidics]], [[optical]] or even [[mechanical]] elements.
'''James (Jim) J. Cramer''' (born [[February 10]], [[1955]] in [[Wyndmoor, Pennsylvania]]) is an American television personality, former [[hedge fund]] manager, and an author. He is currently CNBC's ''[[Mad Money]]'' host, director of [[TheStreet.com]] and host of the radio show ''Real Money with Jim Cramer'' syndicated by Westwood One/CBS Radio.


==Biography==
=== Basic logic gates and mechanical equivalents ===
Jim Cramer grew up in the town of [[Wyndmoor, Pennsylvania]], outside [[Philadelphia]]. He went to [[Springfield Township High School]] in [[Montgomery County, Pennsylvania|Montgomery County]]. He learned the value of a dollar by selling [[ice cream]] at [[Veterans Stadium]] during [[Philadelphia Phillies]] games. Cramer graduated magna cum laude from [[Harvard College]] in 1977 where he was an editor and the President of the [[Harvard Crimson]]. After college, he worked as a journalist at the ''[[Los Angeles Herald Examiner]]''. He went back to school to get a [[Juris Doctor]] degree from [[Harvard Law School]] and, after graduating in 1984, went to work in [[Goldman Sachs|Goldman Sachs]]' Sales & Trading department.


In 1987, he started his own [[hedge fund]] company, Cramer Berkowitz, working out of the offices of hedge fund pioneer Michael Steinhardt's [[Steinhardt, Fine, Berkowitz, Co.]] It was to be the beginning of a shrewd career on Wall Street where he purportedly achieved a 24% compounded return (after all fees) for the next 13 years. After a stellar 2000, Cramer's fund finished up the year +36%, compared to -11% for the [[S&P 500]] and -6% for the [[Dow Jones Industrial Average|Dow Industrials]]. But after the tech bubble burst, Cramer retired from the hedge fund business, turning the company over to his long-time partner, [[Jeff Berkowitz]]. While Cramer's success in producing high returns for his fund was unmistakeable, he began to concentrate on his passion for journalism.
While [[semiconductor]] electronic logic (see later) is preferred in most applications, relays and [[switch]]es are still used in some industrial applications and for educational purposes. In this article, the various types of logic gates are illustrated with drawings of their relay-and-switch implementations, although the reader should remember that these are electrically different from the semiconductor equivalents that are discussed later.


He co-founded [[TheStreet.com]] and is the Markets Commentator and Advisor to the CEO, Thomas Clarke, Jr., and went on to work at [[CNBC]], where he was a host on ''[[America Now]]'' and ''[[Kudlow & Cramer]]'' with [[Lawrence Kudlow]]. He now has a radio show called ''RealMoney Radio'' and his own television show focused on stocks, ''[[Mad Money]] with Jim Cramer''. He exhibits his encyclopedic knowledge of [[equity securities]] during the ''Lightning Round'' segment on ''Mad Money'' where he quickly analyzes stocks suggested by callers. One of the popular catchphrases on ''Mad Money'' is "[[Booyah]]," which seems to have taken the form of a greeting as well as an enthusiastic celebration. Also popular is his ritual of throwing his chair across the studio before the ''Lightning Round'', as well as throwing his book -- ''Jim Cramer's Real Money--Sane Investing in an Insane World'' -- whenever a caller mentions it on air. Thanks to his energetic rhetoric, his insightful analysis of stocks, and his off-the-wall antics, Mad Money has become CNBC's most popular show.
Relay logic was historically important in industrial automation (see [[ladder logic]] and [[programmable logic controller]]). Since relay contacts conduct in both directions, complex logic designs must be checked for "sneak paths" that produce unintended logic paths.


In [[1988]], Cramer married his wife, Karen Backfisch, whom he refers to as the "Trading Goddess." (Karen was a professional trader herself, and Jim claims that she earned the nickname before the two met.) Karen stopped trading full-time after the birth of their first child in July [[1991]]. The couple recently separated. They have two daughters.
Semiconductor logic gates are ''not'' conductive in both directions, as the input signal acts as a 'trigger' to allow current out of the output, rather than allowing current straight through from input to output. However, the following mechanical variations do show the basic principles of the gates without detailing the precise internal workings. For information about how modern semiconductors really work, see [[CMOS]].


Having already made a fortune in the market, he now uses his show, book, and website to help the "common man" become wealthy. He eschews Wall Street orthodoxy, strongly promotes portfolio diversification (generally five stocks, believing that most individuals do not have time to research more than five,) and recommends that people devote 20% of their portfolio to pure speculation because, in the long run, that one "lottery ticket" stock will greatly outweigh the losses. He also strongly encourages viewers to do research before and after investing in stock selections; he is not a fan of the "Cramer bounce" (the phenomenon in after-hours trading where his stock selections suddenly increase in price solely on his recommendation) as he feels those listeners have not "done their homework."
The three types of essential logic gate are the AND, the OR and the NOT gate. With these three, any conceivable boolean equation can be implemented. However, for convenience, the derived types NAND, NOR, XOR and XNOR are also used, which often use fewer circuit elements for a given equation than an implementation based solely on AND, OR and NOT would do. In fact the NAND has the lowest component count of any gate apart from NOT when implemented using modern semiconductor techniques, and since a NAND can implement both a NOT and, by application of [[De Morgan's Law]], an OR function, this single type can effectively replace AND, OR and NOT, making it the only type of gate that is needed in a real system. [[Programmable logic array]]s will very often contain nothing but NAND gates to simplify their internal design.


==== AND gates ====
==Criticism==
Critics often use the nickname "The Weathervane" to describe Cramer, whose outlook will rapidly oscillate between bearish and bullish following the prevailing market sentiment.


A former employee of Cramer's named Nicholas Maier accused Cramer, in his book ''Trading with the Enemy'', of front running stocks by feeding rumors about stocks he held to CNBC's [[Maria Bartiromo]]. Cramer and Bartiromo have denied the allegation.
The first example is the [[logical conjunction|AND]](dont cut and paste tom) gate, whose [[truth tablel]] is shown below, left. The Boolean AND function gay can be represented by a simple circuit with two swu1itches, A and B, as shown below, right. If a power lead is connected to switch A, and a wire connects switches A and B, then both A and B have to be on in order for the circudgdhdit to conduct electricity and provide power. The AND gate can be treated in the same way as the logical AND operator. It is simmply a multiplication operation between the two input variables (A and B) which produces a single output, the product of the two inputs. The value that each input variable takes on is called a "binary digit". This is either a 0 or a 1. Therefore, the output is either a 0 or a 1. Each input and output is "HIGH" or "TRUE" when it takes on the value of 1, whereas it becomes "LOW" or "FALSE" when it represents 0. When the output is TRUE, the circuit is ON, otherwise it is OFF. Therefore, the output of an AND gate will only be TRUE when the two inputs are TRUE. This can be seen in the truth table. A logic gate is a gate of logic. Alow state of 0 and a high state of 1.


He is also said to have exhibited a violent temper at his hedge fund, characterized by screaming at his employees and throwing telephones and computers when he was unhappy with his results. In his interview with [[60 Minutes]], Cramer admits to having had a problem with his temper, and after speaking with his dad (who said he would outlive Cramer if things continued as they were,) Cramer left the hedge fund business. Cramer's reputation as having an anger-management problem has helped him in creating Mad Money, though, as it moves away from typical [[CNBC]] programming.
{{clear}}


Criticism of Jim Cramer has also expanded to the Internet. A number of websites have sprung up with the intention of tracking Cramer’s recommendations. Some are merely [[blog|blogs]] that vent frustrations against Cramer, his onscreen persona, and the stock picks made in the ‘Lightning Round’ of his CNBC show. Other sites go further and analyze Cramer’s stock picks in some detail. Some of the more creative websites use complex programs to track and compare recommendations with the performance of the overall market. One such site, [http://www.cramerwatch.org CramerWatch.org], actually pits Jim Cramer’s recommendations against a [[monkey]] that makes buy or sell recommendations at random. The monkey does as well or better than Cramer.
<table align="left" width="20%" border="1" style="float:left">
<tr bgcolor="#ddeeff" align="center">
<th colspan="2">INPUT</th>
<th>OUTPUT</th>
<tr bgcolor="#ddeeff" align="center">
<td>A</td>
<td>B</td>
<td>A AND B</td>
<tr bgcolor="#ddffdd" align="center">
<td>0</td>
<td>0</td>
<td>0</td>
<tr bgcolor="#ddffdd" align="center">
<td>1</td>
<td>0</td>
<td>0</td>
<tr bgcolor="#ddffdd" align="center">
<td>0</td>
<td>1</td>
<td>0</td>
<tr bgcolor="#ddffdd" align="center">
<td>1</td>
<td>1</td>
<td>1</td>
</table>


==Trivia==
[[Image:circuit and.png|right|frame|Switch circuit diagram for AND gate]]
*Cramer appeared, as himself, in the third season opener and finale of the TV series ''[[Arrested Development (TV series)|Arrested Development]]''.
*Cramer refuses to shave his goatee out of "superstition" (though he has not stated specifically why). CNBC has requested him to do so (the remainder of its broadcasters are clean-shaven); however, since Mad Money is CNBC's highest-rated show, CNBC has apparently not demanded he do so.
*According to the [[January 11]], 2006 edition of "Mad Money," Cramer does not like it when people call him Jimmy. Other episodes, when a caller refers to Jim as "Mr. Cramer," have Cramer saying that Mr. Cramer is his dad.
*On an episode that aired [[January 31]], 2006 Cramer mentioned that he received a mining company stock that is now worthless as a [[Bar Mitzvah]] gift. This was mentioned during the segment on [[Caterpillar Inc.|Caterpillar]] stock (one of his "top 10" American industrial stocks.) He also referred to his father's [[shiv'ah]] - the Jewish ritual period following a death - in his book, "Confessions of a Street Addict." It can thus be inferred that he is, or once was, a member of the Jewish faith, though he has not discussed his religious views publicly.
*In November of 2005, Cramer was featured on the show [[60 Minutes]].
*When a caller talks for too long without mentioning a stock, Cramer has been known to take a blanket and pillow, each with the "Jim Cramer's Mad Money" logo featured prominently, and take a mock-nap.
*The toy bulls and bears that Cramer often plays with on his show (and frequently destroys) have recently become a highly sought-after commodity on [[Ebay]]; he throws them to audience members during the tapings of his show where he has a live audience, and during such events as his "Mad Money College Tour" (he has also purportedly sent them to callers with young children who shout "boo-yah" on his show). The even rarer Jim Cramer talking bobble-heads (he destroys those too) are also highly sought commodities.
*Jim Cramer's 'Cramerica' references are similar to those of the fictional business created by [[Cosmo Kramer]] on [[Seinfeld]] called 'Kramerica'.
*On a special edition of Mad Money, Cramer mentioned that he believed [[Regulation FD]] to be among the best rules ever passed for individual investors. (Cramer recommends investors listen to company conference calls, which now must be broadcast to the public instead of being given to only select institutional investors.)
*He is good friends with New Jersey Governor [[Jon Corzine]].
*He is also good friends with New York Attorney General [[Eliot Spitzer]].
*Jim is a fan of the television show "[[24 (TV series)|24]]" and often makes references to it on air.


==Authorships==
{{clear}}
Cramer has written anecdotal and economics books.
* ''Jim Cramer's Real Money: Sane Investing in an Insane World'' ISBN 0743224892
* ''Confessions of a Street Addict'' ISBN 0743224876
* ''You Got Screwed! Why Wall Street Tanked and How You Can Prosper'' ISBN 074324690X


==== OR gates ====
==Books about Cramer==
* ''Trading With The Enemy'' by Nicholas W. Maier. Maier was sued by Cramer due to a suggestion that Cramer was the subject of an [[SEC]] investigation of [[IPO]] practices. [http://www.internetnews.com/bus-news/article.php/1121251]


==External links==
Another important arrangement is the [[logical disjunction|OR]] gate, whose truth table is shown below, left.
*[http://find.thestreet.com/cgi-bin/texis/find/results.html?nh=10&qt=Mad-Money-Wrap-up&x=9&y=7 TheStreet.com], Cramer's "Mad Money" Recaps
*[http://www.actionalertsplus.com/ ActionAlertPlus.com] - Jim Cramer's charitable trust website-all profit goes to charity
*[http://www.thestreet.com/tsc/podcast Podcast page for Cramer's nationally syndicated radio show.]
*[http://realmoney.cbsradio.com/ Real Money Radio Show]
{{wikiquote}}
*[http://www.cramersmadmoney.com CramersMadMoney.com] - Forum discusses Mad Money show
*[http://www.gracehb.org/markahrens/madmoney.mov Quicktime Video of Jim Cramer's Signature "Lighting Round" on MAD MONEY (6MB)]
*[http://www.thecramerreport.com The Cramer Report] - A daily summary of CNBC's 'Mad Money with Jim Cramer'.
*[http://www.cramerwatch.org CramerWatch.org] - Find out if a monkey is just as good as Jim Cramer's 'Mad Money'.
*[http://madmoneyrecap.com/madmoney_dailysummary_index.htm Mad Money Recap] - Recap of nightly show stock picks and comments
*[http://MadMoneyMachine.com Mad Money Machine] at MadMoneyMachine.com - Blog and Podcast that reviews Jim Cramer's stock picks and other fun investment topics
*[http://www.cramers-mad-money.com Jim Cramer's Mad Money] Jim Cramer's Mad Money & Stop Trading Recaps and Comments
*[http://www.newyorker.com/critics/television/articles/060605crte_television The New Yorker] New Yorker critic's article by Nancy Franklin
*{{imdb name|id=1977586|name=Jim Cramer}}


==References==
An OR gate can be constructed from two switches, arranged so that if either switch is "on", the output will also be "on". Note that the output will still be on even if both switches are on.
#[http://search.barnesandnoble.com/booksearch/isbninquiry.asp?ean=9780743510103&displayonly=CHP Barnes & Noble.com - Fortune Tellers: Inside Wall Street's Game of Money, Media and Manipulation] Chapter One: The King of all Media, Copyright © [[2000]] by [[Howard Kurtz]]
#[http://www.thestreet.com/k/aap/bio.html Action Alerts PLUS - Bio]
#[http://mikesnewsletterinvesting.blogspot.com/2006/03/confessions-of-street-addict.html Book Review]
#[http://www.nbccableinfo.com/insidenbccable/networks/cnbc/prog/people/cramer.html NBC Cable Networks - NBCCableinfo.com - CNBC] James Cramer
#[http://moneycentral.msn.com/content/CNBCTV/TV_Info/P108231.asp MSN Money - CNBC TV: Investing] Mad Money
#[http://www.law.harvard.edu/alumni/bulletin/2001/summer/feature_1-2.html In the Money, continued], ''Balance Sheet'', article about Cramer and other law alumni, from the online ''Harvard Law Bulletin''
#[http://www.shout.net/~mec/cramer-faq.html The Unofficial James Cramer FAQ]


{{clear}}


[[Category:1955 births|Cramer, James]]
<table align="" width="20%" border="1" style="float:left">
[[Category:Living people|Cramer, James]]
<tr bgcolor="#ddeeff" align="center">
[[Category:American financial writers|Cramer, James]]
<th width="66%" colspan="2">INPUT</th>
[[Category:American lawyers|Cramer, James]]
<th width="33%">OUTPUT</th>
[[Category:American money managers|Cramer, James]]
<tr bgcolor="#ddeeff" align="center">
[[Category:American radio personalities|Cramer, James]]
<td>A</td>
[[Category:American television personalities|Cramer, James]]
<td>B</td>
[[Category:Broadcast news analysts|Cramer, James]]
<td>A OR B</td>
[[Category:Business leaders|Cramer, James]]
<tr bgcolor="#ddffdd" align="center">
[[Category:CNBC|Cramer, James]]
<td>0</td>
[[Category:Columnists|Cramer, James]]
<td>0</td>
[[Category:People from Pennsylvania|Cramer, James]]
<td>0</td>
<tr bgcolor="#ddffdd" align="center">
<td>1</td>
<td>0</td>
<td>1</td>
<tr bgcolor="#ddffdd" align="center">
<td>0</td>
<td>1</td>
<td>1</td>
<tr bgcolor="#ddffdd" align="center">
<td>1</td>
<td>1</td>
<td>1</td>
</table>

[[Image:Switch circuit or.png|right|frame|Switch circuit diagram for OR gate]]

{{clear}}

==== NOT gates ====

A simpler arrangement is the [[negation|NOT]] gate, whose truth table is shown opposite.

This is a special switch that when pushed ''breaks'' the current when it is pressed. The normally-closed contact of a relay can be used for this purpose.

{{clear}}

<table align="left" width="20%" border="1" style="float:left">
<tr bgcolor="#ddeeff" align="center">
<th width="50%">INPUT</th>
<th width="50%">OUTPUT</th>
<tr bgcolor="#ddeeff" align="center">
<td>A</td>
<td>NOT A</td>
<tr bgcolor="#ddffdd" align="center">
<td>0</td>
<td>1</td>
<tr bgcolor="#ddffdd" align="center">
<td>1</td>
<td>0</td>
</table>

[[Image:Switch circuit not.png|right|frame|Switch circuit diagram for NOT gate]]

{{clear}}

==== NAND and NOR gates ====

Using NOT gates, also called [[inverter (logic gate)|inverters]], allows us to make alternate versions of the AND and OR gates, by virtue of [[De Morgan's laws|De Morgan's Law]]. Note that the layout of the switches in the two circuits is swapped when we turn the switches "backwards". Also note how the output of the first pair controls the operation of the NOT gate.

[[Image:Switch alternate and or.png|left|frame|Switch diagram of alternate AND and OR gates]]

This may seem like an unnecessary complication, but in fact this is very useful. By removing the NOT gate from these alternate circuits, we create the so-called [[logical nand|NAND]] (for NOT-AND) and [[logical nor|NOR]] (for NOT-OR) gates. This is also important because transistors acting as switches are by their nature inverting devices.

{{clear}}

===== NAND =====

<table align="left" border="1">
<tr bgcolor="#ddeeff" align="center">
<th colspan="2">INPUT</th>
<th>OUTPUT</th>
<tr bgcolor="#ddeeff" align="center">
<td>A</td>
<td>B</td>
<td>A NAND B</td>
<tr bgcolor="#ddffdd" align="center">
<td>0</td>
<td>0</td>
<td>1</td>
<tr bgcolor="#ddffdd" align="center">
<td>1</td>
<td>0</td>
<td>1</td>
<tr bgcolor="#ddffdd" align="center">
<td>0</td>
<td>1</td>
<td>1</td>
<tr bgcolor="#ddffdd" align="center">
<td>1</td>
<td>1</td>
<td>0</td>
</table>

[[Image:Switch_NAND.jpg|frame|right|Switch circuit diagram of NAND gate]]

{{clear}}

===== NOR =====

<table width=20%" align=left border="1">
<tr bgcolor="#ddeeff" align="center">
<th colspan="2">INPUT</th>
<th>OUTPUT</th>
<tr bgcolor="#ddeeff" align="center">
<td>A</td>
<td>B</td>
<td>A NOR B</td>
<tr bgcolor="#ddffdd" align="center">
<td>0</td>
<td>0</td>
<td>1</td>
<tr bgcolor="#ddffdd" align="center">
<td>1</td>
<td>0</td>
<td>0</td>
<tr bgcolor="#ddffdd" align="center">
<td>0</td>
<td>1</td>
<td>0</td>
<tr bgcolor="#ddffdd" align="center">
<td>1</td>
<td>1</td>
<td>0</td>
</table>

[[Image:Switch_NOR.jpg|frame|right|Switch circuit diagram of NOR gate]]

{{clear}}

==== XOR and XNOR gates ====

There exist two other 'basic' logic gates - [[XOR]] (exclusive-OR)and [[XNOR]] (exclusive-NOR).

{{clear}}

<table width=20%" border="1" align=right>
<tr bgcolor="#ddeeff" align="center">
<th colspan="2">INPUT</th>
<th>OUTPUT</th>
<tr bgcolor="#ddeeff" align="center">
<td>A</td>
<td>B</td>
<td>A XOR B</td>
<tr bgcolor="#ddffdd" align="center">
<td>0</td>
<td>0</td>
<td>0</td>
<tr bgcolor="#ddffdd" align="center">
<td>0</td>
<td>1</td>
<td>1</td>
<tr bgcolor="#ddffdd" align="center">
<td>1</td>
<td>0</td>
<td>1</td>
<tr bgcolor="#ddffdd" align="center">
<td>1</td>
<td>1</td>
<td>0</td>
</table>

XOR is a 'stricter' version of the OR gate. Rather than allowing the output to be HIGH when either one or both of the inputs are HIGH, an XOR gate has a HIGH output only when only ''one'' input is HIGH. As such it has the truth table shown to the right. This can also be interpreted (for a two-input gate) as "HIGH output when the inputs are different".

{{clear}}



<table width=20%" border="1" align=right>
<tr bgcolor="#ddeeff" align="center">
<th colspan="2">INPUT</th>
<th>OUTPUT</th>
<tr bgcolor="#ddeeff" align="center">
<td>A</td>
<td>B</td>
<td>A XNOR B</td>
<tr bgcolor="#ddffdd" align="center">
<td>0</td>
<td>0</td>
<td>1</td>
<tr bgcolor="#ddffdd" align="center">
<td>1</td>
<td>0</td>
<td>0</td>
<tr bgcolor="#ddffdd" align="center">
<td>0</td>
<td>1</td>
<td>0</td>
<tr bgcolor="#ddffdd" align="center">
<td>1</td>
<td>1</td>
<td>1</td>
</table>

XNOR is an inverted version of the XOR gate. As such it has the truth table shown to the right. This can also be interpreted as "HIGH output when the inputs are same".

{{clear}}

The preceding simple logic gates can be combined to form more complicated boolean logic circuits. Logic circuits are often classified in two groups: [[combinatorial logic]], in which the outputs are continuous-time functions of the inputs, and [[sequential logic]], in which the outputs depend on information stored by the circuits as well as on the inputs.

----

=== Background ===

The simplest form of electronic logic is [[diode]] logic. This allows AND and OR gates to be built, but not inverters, and so is an incomplete form of logic. To build a complete logic system, [[thermionic valve|valves]] or [[transistor]]s can be used. The simplest family of logic gates using bipolar transistors is called [[resistor-transistor logic]], or RTL. Unlike diode logic gates, RTL gates can be cascaded indefinitely to produce more complex logic functions. These gates were used in early [[integrated circuit]]s. For higher speed, the resistors used in RTL were replaced by diodes, leading to [[diode-transistor logic]], or DTL. It was then discovered that one transistor could do the job of two diodes in the space of one diode, so [[transistor-transistor logic]], or TTL, was created. In some types of chip, to reduce size and power consumption still further, the bipolar transistors were replaced with complementary [[field-effect transistor]]s ([[MOSFET]]s), resulting in complementary metal-oxide-semiconductor ([[CMOS]]) logic.

For small-scale logic, designers now use prefabricated logic gates from [[Logic families|families of devices]] such as the [[TTL]] [[7400 series]] invented by [[Texas Instruments]] and the [[CMOS]] [[4000 series]] invented by [[RCA]], and their more recent descendants. These devices usually contain transistors with multiple emitters, used to implement the AND function, which are not available as separate components. Increasingly, these fixed-function logic gates are being replaced by [[programmable logic device]]s, which allow designers to pack a huge number of mixed logic gates into a single [[integrated circuit]]. The field-programmable nature of [[programmable logic device]]s such as [[FPGA]]s has removed the 'hard' property of hardware; it is now possible to change the logic design of a hardware system by reprogramming some of its components, thus allowing the features or function of a hardware implementation of a logic system to be changed.

Electronic logic gates differ significantly from their relay-and-switch equivalents. They are much faster, consume much less power, and are much smaller (all by a factor of a million or more in most cases). Also, there is a fundamental structural difference. The switch circuit creates a continuous metallic path for current to flow (in either direction) between its input and its output. The semiconductor logic gate, on the other hand, acts as a high-gain [[voltage]] [[electronic amplifier|amplifier]], which sinks a tiny current at its input and produces a low-impedance voltage at its output. It is not possible for current to flow between the output and the input of a semiconductor logic gate.

Another important advantage of standardised semiconductor logic gates, such as the 7400 and 4000 families, is that they are cascadable. This means that the output of one gate can be wired to the inputs of one or several other gates, and so on ''ad infinitum'', enabling the construction of circuits of arbitrary complexity without requiring the designer to understand the internal workings of the gates.

In practice, the output of one gate can only drive a finite number of inputs to other gates, a number called the '[[fanout]] limit', but this limit is rarely reached in the newer [[CMOS]] logic circuits, as compared to [[TTL]] circuits. Also, there is always a delay, called the '[[propagation delay]]', from a change in input of a gate to the corresponding change in its output. When gates are cascaded, the total propagation delay is approximately the sum of the individual delays, an effect which can become a problem in high-speed circuits.

=== Logic levels ===

The two logic levels in binary logic circuits can be described as two voltage ranges, "zero" and "one", or "high" and "low". Each technology has its own requirements for the voltages used to represent the two logic levels, to ensure that the output of any device can reliably drive the input of the next device. Usually, two non-overlapping voltage ranges, one for each level, are defined. The difference between the high and low levels ranges from 0.7 volts in ECL logic to around 28 volts in relay logic.

=== Logic gates and hardware ===

NAND and NOR logic gates are the two pillars of logic, in that all other types of Boolean logic gates (i.e., AND, OR, NOT, [[exclusive or|XOR]], [[exclusive nor|XNOR]]) can be created from a suitable network of just NAND or just NOR gate(s). They can be built from relays or transistors, or any other technology that can create an inverter and a two-input AND or OR gate.

These functions can be seen in the table below.
{| border="1"
|OR||Any high input will drive the output high
|-
|NOR||Any high input will drive the output low
|-
|AND||Any low input will drive the output low
|-
|NAND||Any low input will drive the output high
|}

Logic gates are a vital part of many digital circuits, and as such, every kind is available as an IC. For examples, see the [[4000 series]] of [[CMOS]] logic chips.

=== Symbols ===

There are two sets of symbols in common use, both now defined by [[ANSI]]/[[Institute of Electrical and Electronics Engineers|IEEE]] Std 91-1984 and its supplement ANSI/IEEE Std 91a-1991. The "distinctive shape" set, based on traditional schematics, is used for simple drawings and is quicker to draw by hand. It is sometimes unofficially described as "military", reflecting its origin if not its modern usage. The "rectangular shape" set, based on [[International Electrotechnical Commission|IEC]] 60617-12, has rectangular outlines for all types of gate, and allows representation of a much wider range of devices than is possible with the traditional symbols. The IEC's system has been adopted by other standards, such as [[EN]] 60617-12:1999 in Europe and [[British Standard|BS]] EN 60617-12:1999 in the United Kingdom.

{| border="1"
!Type!!Distinctive shape!!Rectangular shape
|-
|'''AND'''||[[image:and.png|AND symbol]]||[[image:IEC_AND.gif|AND symbol]]
|-
|'''OR'''||[[image:or-gate.png|OR symbol]]||[[image:IEC_OR.gif|OR symbol]]
|-
|'''NOT'''||[[image:not-gate.png|NOT symbol]]||[[image:IEC_NOT.gif|NOT symbol]]
|-
| colspan="3" |In electronics a NOT gate is more commonly called an inverter. The circle on the symbol is called a ''bubble'', and is generally used in circuit diagrams to indicate an inverted input or output.
|-
|'''NAND'''||[[image:nand-gate.png|NAND symbol]]||[[image:IEC_NAND.gif|NAND symbol]]
|-
|'''NOR'''||[[image:nor-gate.png|NOR symbol]]||[[image:IEC_NOR.gif|NOR symbol]]
|-
| colspan="3" |In practice, the cheapest gate to manufacture is usually the NAND gate. Additionally, [[Charles Peirce]] showed that NAND gates alone (as well as NOR gates alone) can be used to reproduce all the other logic gates.

Symbolically, a NAND gate can also be shown using the OR shape with bubbles on its inputs, and a NOR gate can be shown as an AND gate with bubbles on its inputs. This reflects the equivalency due to De Morgans law, but it also allows a diagram to be read more easily, or a circuit to be mapped onto available physical gates in packages easily, since any circuit node that has bubbles at both ends can be replaced by a simple bubble-less connection and a suitable change of gate. If the NAND is drawn as OR with input bubbles, and a NOR as AND with input bubbles, this gate substitution occurs automatically in the diagram (effectively, bubbles "cancel"). This is commonly seen in real logic diagrams - thus the reader must not get into the habit of associating the shapes exclusively as OR or AND shapes, but also take into account the bubbles at both inputs and outputs in order to determine the "true" logic function indicated.

Two more gates are the exclusive-OR or XOR function and its inverse, exclusive-NOR or XNOR. The two input Exclusive-OR is true only when the two input values are ''different'', false if they are equal, regardless of the value. If there are more than two inputs, the gate generates a true at its output if the number of trues at its input is ''odd'' ([http://www-inst.eecs.berkeley.edu/~cs61c/resources/dg-BOOL-handout.pdf]). In practice, these gates are built from combinations of simpler logic gates.
|-
|'''XOR'''||[[image:xor-gate.png|XOR symbol]]||[[image:IEC_XOR.gif|XOR symbol]]
|-
|'''XNOR'''||[[image:xnor-gate.png|XNOR symbol]]||[[image:IEC_XNOR.gif|XNOR symbol]]
|}

[[Image:7400.jpg|thumb|180px|The 7400 chip, containing four NAND's. The two additional contacts supply power (+5 V) and connect the ground. ]]

===DeMorgan equivalent symbols===

By use of [[De Morgan's laws|De Morgan's theorem]], an ''AND'' gate can be turned into an ''OR'' gate by inverting the sense of the logic at its inputs and outputs. This leads to a separate set of symbols with inverted inputs and the opposite core symbol. These symbols can make circuit diagrams for circuits using [[active low]] signals much clearer and help to show accidental connection of an active high output to an active low input or vice-versa.
<!--i'll add the symbols later-->
<!--could this be integrated with the tedious discussion of symbols? -->

=== Storage of bits ===

Related to the concept of logic gates (and also built from them) is the idea of storing a bit of information. The gates discussed up to here cannot store a value: when the inputs change, the outputs immediately react. It is possible to make a storage element either through a [[capacitor]] (which stores charge due to its physical properties) or by feedback. Connecting the output of a gate to the input causes it to be put through the logic again, and choosing the feedback correctly allows it to be preserved or modified through the use of other inputs. A set of gates arranged in this fashion is known as a "latch", and more complicated designs that utilise [[Clock signal|clock]]s (signals that oscillate with a known period) and change only on the rising edge are called edge-triggered "[[flip-flop (electronics)|flip-flop]]s". The combination of multiple flip-flops in parallel, to store a multiple-bit value, is known as a register.

These registers or capacitor-based circuits are known as computer [[computer storage|memory]]. They vary in performance, based on factors of speed, complexity, and reliability of storage, and many different types of designs are used based on the application.

=== Three-state logic gates ===

Three-state, or 3-state, logic gates have three states of the output: high (H), low (L) and high-impedance (Z). The high-impedance state plays no role in the logic, which remains strictly binary. These devices are used on [[Electrical bus|bus]]es to allow multiple chips to send data. A group of three-states driving a line with a suitable control circuit is basically equivalent to a [[multiplexer]], which may be physically distributed over separate devices or plug-in cards.

'Tri-state', a widely-used synonym of 'three-state', is a trademark of the [[National Semiconductor|National Semiconductor Corporation]].

=== Miscellaneous ===

Logic circuits include such devices as [[multiplexer]]s, [[processor register|registers]], [[ALU]]s, and [[computer storage|computer memory]], all the way up through complete [[microprocessor]]s which can contain more than a million gates. In practice, the gates are made from [[field effect transistor]]s (FETs), particularly metal-oxide-semiconductor FETs ([[MOSFET]]s).

In [[reversible]] logic, [[Toffoli gate]]s are used.

== History and development ==

The earliest logic gates were made mechanically. [[Charles Babbage]], around 1837, devised the [[Analytical Engine]]. His logic gates relied on mechanical gearing to perform operations. Electromagnetic relays were later used for logic gates. In 1891, [[Almon Strowger]] patented a device containing a logic gate switch circuit ({{US patent|447918}}). Strowger's patent was not in widespread use until the 1920s. Starting in 1898, [[Nikola Tesla]] filed for [[patent]]s of devices containing logic gate circuits (see [[List of Tesla patents]]). Eventually, vacuum tubes replaced relays for logic operations. [[Lee De Forest]]'s modification, in 1907, of the [[vacuum tube|Fleming valve]] can be used as AND logic gate. [[Claude E. Shannon]] introduced the use of Boolean algebra in the analysis and design of switching circuits in [[1937]]. [[Walther Bothe]], inventor of the [[coincidence circuit]], got part of the [[1954]] [[Nobel Prize]] in physics, for the first modern electronic AND gate in [[1924]]. Active research is taking place in [[molecular logic gate]]s.

== Common Basic Logic ICs ==

{|
!CMOS!!TTL!!Function
|-
|[[4001]]||[[7402]]||Quad two-input NOR gate
|-
|[[4011]]||[[7400]]||Quad two-input NAND gate
|-
|[[4049]]||[[7404]]||Hex NOT gate (inverting [[buffer]])
|-
|[[4070]]||[[7486]]||Quad two-Input XOR gate
|-
|[[4071]]||[[7432]]||Quad two-input OR gate
|-
|[[4077]]||[[74266]]||Quad two-input XNOR gate
|-
|[[4081]]||[[7408]]||Quad two-input AND gate
|}

For more CMOS logic ICs, including gates with more than two inputs, see [[4000 series]].

== See also ==

* [[Digital circuit]]
* [[Fanout]]
* [[Karnaugh map]]
* [[List of Boolean algebra topics]]
* [[Logic families|Families of logic devices]]
* [[NMOS logic]]
* [[Race hazard]]
* [[Venn diagram]]
* [[Reversible computing]]

== External links and references ==

* ''[http://www.uq.edu.au/_School_Science_Lessons/39.4.01.GIF Symbols for logic gates]''. Twenty First Century Books, Breckenridge, CO.
* ''[http://www.tfcbooks.com/teslafaq/q&a_024.htm Tesla's invention of the AND logic gate]''. Twenty First Century Books, Breckenridge, CO.
* ''[http://www.tfcbooks.com/articles/control.htm Wireless Remote Control and the Electronic Computer Logic Gate]''. Twenty First Century Books, Breckenridge, CO.
* Anderson, Leland I., "''Nikola Tesla — Guided Weapons & Computer Technology''". ISBN 0-9636012-5-3
* Bigelow, Ken, "''[http://www.play-hookey.com/digital/electronics/ How logic gates work internally (for several logic families)]''", play-hookey.com.
* C. E. Shannon, "''A symbolic analysis of relay and switching circuits''," Transactions American Institute of Electrical Engineers, vol. 57, pp. 713-723, March 1938.
* The [[International Electrotechnical Commission|IEC]] symbols are defined in IEC 60617-12 (1997-12), ''Graphical symbols for diagrams - Part 12: Binary logic elements''
* "''[http://goldfish.ikaruga.co.uk/logic.html LEGO Logic Gates]''". goldfish.org.uk, 2005.

== Further reading ==

* Bostock, Geoff, "''Programmable logic devices : technology and applications''". New York, McGraw-Hill, c1988. ISBN 0070066116
* Brown, Stephen D. et. al., "''Field-programmable gate arrays''". Boston, Kluwer Academic Publishers, c1992. The Kluwer international series in engineering and computer science. ISBN 0792392485
* Awschalom, D., D. Loss, and N. Samarth, "''Semiconductor spintronics and quantum computation''". Berlin, Springer, c2002. ISBN 3540421769

[[Category:Logic gates]]

[[bg:Логически елемент]]
[[cs:Logický člen]]
[[da:Gate (digital elektronik)]]
[[de:Logikgatter]]
[[es:Puerta lógica]]
[[fr:Fonction logique]]
[[gl:Porta lóxica]]
[[he:שער לוגי]]
[[lt:Loginis elementas]]
[[nl:Logische poort]]
[[ja:論理回路]]
[[pl:Bramka logiczna]]
[[pt:Porta lógica]]
[[sr:Логичка капија]]
[[fi:Looginen portti]]
[[sv:Logiska grindar]]
[[tr:Mantıksal kapılar]]
[[zh:邏輯門]]

Revision as of 19:31, 8 June 2006

File:Mad Money with Jim Cramer logo.jpg
Mad Money logo

James (Jim) J. Cramer (born February 10, 1955 in Wyndmoor, Pennsylvania) is an American television personality, former hedge fund manager, and an author. He is currently CNBC's Mad Money host, director of TheStreet.com and host of the radio show Real Money with Jim Cramer syndicated by Westwood One/CBS Radio.

Biography

Jim Cramer grew up in the town of Wyndmoor, Pennsylvania, outside Philadelphia. He went to Springfield Township High School in Montgomery County. He learned the value of a dollar by selling ice cream at Veterans Stadium during Philadelphia Phillies games. Cramer graduated magna cum laude from Harvard College in 1977 where he was an editor and the President of the Harvard Crimson. After college, he worked as a journalist at the Los Angeles Herald Examiner. He went back to school to get a Juris Doctor degree from Harvard Law School and, after graduating in 1984, went to work in Goldman Sachs' Sales & Trading department.

In 1987, he started his own hedge fund company, Cramer Berkowitz, working out of the offices of hedge fund pioneer Michael Steinhardt's Steinhardt, Fine, Berkowitz, Co. It was to be the beginning of a shrewd career on Wall Street where he purportedly achieved a 24% compounded return (after all fees) for the next 13 years. After a stellar 2000, Cramer's fund finished up the year +36%, compared to -11% for the S&P 500 and -6% for the Dow Industrials. But after the tech bubble burst, Cramer retired from the hedge fund business, turning the company over to his long-time partner, Jeff Berkowitz. While Cramer's success in producing high returns for his fund was unmistakeable, he began to concentrate on his passion for journalism.

He co-founded TheStreet.com and is the Markets Commentator and Advisor to the CEO, Thomas Clarke, Jr., and went on to work at CNBC, where he was a host on America Now and Kudlow & Cramer with Lawrence Kudlow. He now has a radio show called RealMoney Radio and his own television show focused on stocks, Mad Money with Jim Cramer. He exhibits his encyclopedic knowledge of equity securities during the Lightning Round segment on Mad Money where he quickly analyzes stocks suggested by callers. One of the popular catchphrases on Mad Money is "Booyah," which seems to have taken the form of a greeting as well as an enthusiastic celebration. Also popular is his ritual of throwing his chair across the studio before the Lightning Round, as well as throwing his book -- Jim Cramer's Real Money--Sane Investing in an Insane World -- whenever a caller mentions it on air. Thanks to his energetic rhetoric, his insightful analysis of stocks, and his off-the-wall antics, Mad Money has become CNBC's most popular show.

In 1988, Cramer married his wife, Karen Backfisch, whom he refers to as the "Trading Goddess." (Karen was a professional trader herself, and Jim claims that she earned the nickname before the two met.) Karen stopped trading full-time after the birth of their first child in July 1991. The couple recently separated. They have two daughters.

Having already made a fortune in the market, he now uses his show, book, and website to help the "common man" become wealthy. He eschews Wall Street orthodoxy, strongly promotes portfolio diversification (generally five stocks, believing that most individuals do not have time to research more than five,) and recommends that people devote 20% of their portfolio to pure speculation because, in the long run, that one "lottery ticket" stock will greatly outweigh the losses. He also strongly encourages viewers to do research before and after investing in stock selections; he is not a fan of the "Cramer bounce" (the phenomenon in after-hours trading where his stock selections suddenly increase in price solely on his recommendation) as he feels those listeners have not "done their homework."

Criticism

Critics often use the nickname "The Weathervane" to describe Cramer, whose outlook will rapidly oscillate between bearish and bullish following the prevailing market sentiment.

A former employee of Cramer's named Nicholas Maier accused Cramer, in his book Trading with the Enemy, of front running stocks by feeding rumors about stocks he held to CNBC's Maria Bartiromo. Cramer and Bartiromo have denied the allegation.

He is also said to have exhibited a violent temper at his hedge fund, characterized by screaming at his employees and throwing telephones and computers when he was unhappy with his results. In his interview with 60 Minutes, Cramer admits to having had a problem with his temper, and after speaking with his dad (who said he would outlive Cramer if things continued as they were,) Cramer left the hedge fund business. Cramer's reputation as having an anger-management problem has helped him in creating Mad Money, though, as it moves away from typical CNBC programming.

Criticism of Jim Cramer has also expanded to the Internet. A number of websites have sprung up with the intention of tracking Cramer’s recommendations. Some are merely blogs that vent frustrations against Cramer, his onscreen persona, and the stock picks made in the ‘Lightning Round’ of his CNBC show. Other sites go further and analyze Cramer’s stock picks in some detail. Some of the more creative websites use complex programs to track and compare recommendations with the performance of the overall market. One such site, CramerWatch.org, actually pits Jim Cramer’s recommendations against a monkey that makes buy or sell recommendations at random. The monkey does as well or better than Cramer.

Trivia

  • Cramer appeared, as himself, in the third season opener and finale of the TV series Arrested Development.
  • Cramer refuses to shave his goatee out of "superstition" (though he has not stated specifically why). CNBC has requested him to do so (the remainder of its broadcasters are clean-shaven); however, since Mad Money is CNBC's highest-rated show, CNBC has apparently not demanded he do so.
  • According to the January 11, 2006 edition of "Mad Money," Cramer does not like it when people call him Jimmy. Other episodes, when a caller refers to Jim as "Mr. Cramer," have Cramer saying that Mr. Cramer is his dad.
  • On an episode that aired January 31, 2006 Cramer mentioned that he received a mining company stock that is now worthless as a Bar Mitzvah gift. This was mentioned during the segment on Caterpillar stock (one of his "top 10" American industrial stocks.) He also referred to his father's shiv'ah - the Jewish ritual period following a death - in his book, "Confessions of a Street Addict." It can thus be inferred that he is, or once was, a member of the Jewish faith, though he has not discussed his religious views publicly.
  • In November of 2005, Cramer was featured on the show 60 Minutes.
  • When a caller talks for too long without mentioning a stock, Cramer has been known to take a blanket and pillow, each with the "Jim Cramer's Mad Money" logo featured prominently, and take a mock-nap.
  • The toy bulls and bears that Cramer often plays with on his show (and frequently destroys) have recently become a highly sought-after commodity on Ebay; he throws them to audience members during the tapings of his show where he has a live audience, and during such events as his "Mad Money College Tour" (he has also purportedly sent them to callers with young children who shout "boo-yah" on his show). The even rarer Jim Cramer talking bobble-heads (he destroys those too) are also highly sought commodities.
  • Jim Cramer's 'Cramerica' references are similar to those of the fictional business created by Cosmo Kramer on Seinfeld called 'Kramerica'.
  • On a special edition of Mad Money, Cramer mentioned that he believed Regulation FD to be among the best rules ever passed for individual investors. (Cramer recommends investors listen to company conference calls, which now must be broadcast to the public instead of being given to only select institutional investors.)
  • He is good friends with New Jersey Governor Jon Corzine.
  • He is also good friends with New York Attorney General Eliot Spitzer.
  • Jim is a fan of the television show "24" and often makes references to it on air.

Authorships

Cramer has written anecdotal and economics books.

  • Jim Cramer's Real Money: Sane Investing in an Insane World ISBN 0743224892
  • Confessions of a Street Addict ISBN 0743224876
  • You Got Screwed! Why Wall Street Tanked and How You Can Prosper ISBN 074324690X

Books about Cramer

  • Trading With The Enemy by Nicholas W. Maier. Maier was sued by Cramer due to a suggestion that Cramer was the subject of an SEC investigation of IPO practices. [1]
Wikiquote has quotations related to Jim Cramer.

References

  1. Barnes & Noble.com - Fortune Tellers: Inside Wall Street's Game of Money, Media and Manipulation Chapter One: The King of all Media, Copyright © 2000 by Howard Kurtz
  2. Action Alerts PLUS - Bio
  3. Book Review
  4. NBC Cable Networks - NBCCableinfo.com - CNBC James Cramer
  5. MSN Money - CNBC TV: Investing Mad Money
  6. In the Money, continued, Balance Sheet, article about Cramer and other law alumni, from the online Harvard Law Bulletin
  7. The Unofficial James Cramer FAQ
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