Tuesday, June 16, 2015

NI Multisim: 74ls181 ALU 4-Bit Logic Unit TTL

74ls181 ALU 4-Bit Logic Unit TTL

What does a 4-Bit ALU do?

Written by: Larsha Johnson
6/16/2015

The 74181 is still used today in retro hacker projects. Here's ow it works and why it's so strange. Is it an all in one logic chip? Well, yes. Since it provides 16 Arithmetic Operations Add, Subtract, Compare, Double, Plus Twelve Other Arithmetic Operations as well as provides all 16 Logic Operations of Two Variables Exclusive — OR( XOR), Compare, AND, NAND, OR, NOR, Plus Ten other Logic Operations!

Why was it designed? To make computing faster in comparison with standard logic gates that was what available at the time. In March 1970, Texas Instruments introduced the 74181 Arithmetic / Logic Unit (ALU) chip, which put a full 4-bit ALU on one fast TTL chip. This chip provided 32 arithmetic and logic functions, as well as carry lookahead for high performance. 

The SN54/74LS181 is a 4-bit Arithmetic Logic Unit (ALU) which can perform all the possible 16 logic, operations on two variables and a variety of arithmetic operations.

The 74181 ALU (arithmetic/logic unit) chip powered many of the minicomputers of the 1970s: it provided fast 4-bit arithmetic and logic functions, and could be combined to handle larger words, making it a key part of many CPUs.

The 74181 is a 4-bit slice arithmetic logic unit (ALU), implemented as a 7400 series TTL integrated circuit. The first complete ALU on a single chip,[1] it was used as the arithmetic/logic core in the CPUs of many historically significant minicomputers and other devices.

The 74181 represents an evolutionary step between the CPUs of the 1960s, which were constructed using discrete logic gates, and today's single-chip microprocessor CPUs. Although no longer used in commercial products, the 74181 is still referenced in computer organization textbooks and technical papers. It is also sometimes used in 'hands-on' college courses, to train future computer architects. 

 
• Provides 16 Arithmetic Operations Add, Subtract, Compare, Double,
Plus Twelve Other Arithmetic Operations 
Provides all 16 Logic Operations of Two Variables Exclusive — OR,
Compare, AND, NAND, OR, NOR, Plus Ten other Logic Operations
• Full Lookahead for High Speed Arithmetic Operation on Long Words
• Input Clamp Diodes

 FUNCTIONAL DESCRIPTION

The SN54/74LS181 is a 4-bit high speed parallel Arithmetic Logic Unit (ALU). Controlled by the four Function Select Inputs (S0 . . . S3) and the Mode Control Input (M), it can perform all the 16 possible logic operations or 16 different arithmetic operations on active HIGH or active LOW operands. The Function Table lists these operations.


The combinational logic circuitry of the 74181 integrated circuit


Reference articles


I sell on Tindie

Sunday, May 3, 2015

NI Multisim - SYNCHRONOUS 4-BIT COUNTER 74ls163

74LS163
74LS Series
  • Synchronous 4-bit counter
  • Dual-In-Line Package
  • 16 pins

http://www.cse.hcmut.edu.vn/~hoangha/uploads/DigitalSystemProject/digitalsystemlab/lab4_2.htm

Tuesday, April 28, 2015

NI Multisim: Hall Effect Sensor & Magnetic Flux

NI Multisim: Hall Effect Sensor & Magnetic Flux

Written by Larsha Johnson
4/28/2015



Build a magnetic switch using a Hall Effect sensor in Multisim. In its simplest form, the sensor operates as an analog transducer, directly returning a voltage. With a known magnetic field, its distance from the Hall plate can be determined. Using groups of sensors, the relative position of the magnet can be deduced.

Hall Effect Sensors convert magnetic flux to a voltage. The output voltage of the sensor depends on the magnetic flux density.

Use this device in conjunction with either the Magnetic Flux Source or the Magnetic Flux Generator. Refer to the Magnetic Flux Source and Magnetic Flux Generator sections for more information.

This topic refers to education-specific features of Multisim

Other components used to simulate the design include the magnetic flux source and magnetic flux generator. These are recommended for simulation studies.

Magnetic Flux Source

This device is used with a Hall Effect Sensor.

The Magnetic Flux Source uses the default B key to change the density and polarity of the magnetic flux impacting on a Hall Effect Sensor. You must specify the sphere of influence of the magnetic flux source by entering an integer value in the Magnetic Channel field in the Value tab of the component’s properties dialog box.

The Magnetic Channel field on the Hall Effect Sensor must have a matching integer value for that sensor to be influenced by the source. No two magnetic flux sources or generators should have the same integer value in the Magnetic Channel field. You can have as many Hall Effect Sensors as you wish to react to any given source/generator and as many different sources/generators as desired as long as each source/generator has a different integer value.

Magnetic Flux Generator

This device is used with a Hall Effect Sensor.

 To locate Hall Effect Sensors, click Search from the Select a Component dialog box, and enter *hall effect sensor* in the Function field.

The Magnetic Flux Generator produces a continuous varying magnetic field (sinusoidal with N and S peaks). You can define the flux density, rate of rotation (translating to frequency) and specify the sphere of influence of the generator by putting a unique integer value in the Magnetic Channel field in the Value tab of the source’s properties dialog box.

The Magnetic Channel field on the Hall Effect Sensor must have a matching integer value for that sensor to be influenced by the generator. No two magnetic flux generators or sources should have the same integer value in the Magnetic Channel field. You can have as many Hall Effect Sensors as you wish to react to any given source/generator and as many different sources/generators as desired as long as each source/generator has a different integer value


HP 50g - Step-by-Step Mode

Friday, April 3, 2015

Stroboscope - Motion of a wild cat

The stroboscopic effect is a visual phenomenon caused by aliasing that occurs when continuous motion is represented by a series of short or instantaneous samples. It occurs when the view of a moving object is represented by a series of short samples as distinct from a continuous view, and the moving object is in rotational or other cyclic motion at a rate close to the sampling rate. It also accounts for the "wagon-wheel effect", so-called because in video or film, spoked wheels on horse-drawn wagons sometimes appear to be turning backwards.
A strobe fountain, a stream of water droplets falling at regular intervals lit with a strobe light, is an example of the stroboscopic effect being applied to a cyclic motion that is not rotational. When viewed under normal light, this is a normal water fountain. When viewed under a strobe light with its frequency tuned to the rate at which the droplets fall, the droplets appear to be suspended in mid-air. Adjusting the strobe frequency can make the droplets seemingly move slowly up or down. 

HP 50g - Graphing Rose Petals - Polar Graphs

Graphing Rose Petals - HP50g

Written by: Larsha Johnson
4/3/2015

How to graph a rose petal on the HP50g. Rose curve equations have two forms: 
  1. r = a cos(nθ) and 
  2. r = a sin(nθ) 
where a ≠ 0 and n is a positive integer. Petals have length determined by a. If n is odd, the number of petals is n. However, if n is even, the number of petals is 2n.

The simplicity and symmetry of Rhodonea or rose curves have fascinated mathematicians since they were first named by the Italian mathematician Guido Grandi in the 1700s. We were fascinated by an interesting pattern created by counting the number of petals of these curves.



In mathematics, a rose or rhodonea curve is a sinusoid plotted in polar coordinates. This concept is studied in Precalculus or Calculus.

Students will understand the role of the values of a and n in the equation r = asin(nθ).
Students will be able to predict the number of petals and their length by examining the polar equation.
Student will understand the relationship between the equation of a rose curve and the equation of a sinusoidal function.

Vocabulary
amplitude
frequency
rose curve
sinusoidal function

Touch Switch Circuit - 2N3904

HP 50g - Double Integrals in Equation Writer

Use your HP 50g to solve Double Integrals in Calculus 3. New videos every Sunday. Grab your graphing calculator and Subscribe. See you there.

HP 50g - Periodic Table

The HP 50g is a powerful calculator. Find out just what it can do every Sunday. Subscribe to our YouTube Channel. Bits4Bots


LabVIEW Multisim API Toolkit - RLC Values Example

Automate your Multisim design in LabVIEW  Written by: Larsha Johnson Date: October 24th, 2021 If you like designing electronic circuits in M...

Popular Post