Logic Circuits
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The following is one of the most rare and special documents here at the DigiBarn, the only known copy of the complete schematic specification of the 512K Macintosh Logic Board. Daniel Kottke co-authored this design which served as the basis for the 64K.... -
This circuit is a Logic Probe. It indicates the logic state of the node of any TTL logic circuit. To do that, we have to supply the probe with the same power of the circuit that we want to analyse: same Vcc and same GND. To check the logic level, we must.... -
A simple 5 Volt regulated PSU featuring overvoltage protection. The 5 volt regulated power supply for TTL and 74LS series integrated circuits, has to be v.... -
This simple logic probe has both LEDs on with no signal at the input but due to the nor gates connected to the probe, indicates correctly when a high or low signal is present. It also works correctly for pulse trains. Normally both LEDs are forward biased.... -
Logic probe is useful tool to measure, in a check digital circuits. As a meter, which is used to measure power in electrical circuits. Logic probe was used for.... -
The liquid detector is a detector with liquid alternating voltage and can be built using some common electronic components. Voltage alternative for this circuit is made using a gate with Schmit trigger function, which works as an alternative power.... -
Electronics Tutorial about Combinational Logic Circuits that use Logic Gates to make Multiplexers, Encoders and Solid State Switches.... -
Digital Electronics Tutorial about the Logic NOT Gate also called an Inverter and the Logic NOT Gate Truth Table used in TTL and CMOS Logic Gate circuits.... -
Here is a simple logic state indicator to test whether the output of digital IC is in logic 1 or 0. The Bicolor LED lights Green when the logic state is 1.... -
Logic testers are simple but very helpful devices in testing digital circuits. A logic probe can be designed in many different ways. In this particular des.... -
The schematic below illustrates 4 methods of controlling a relay with a digital logic signal. Figure (A) can probably be used in most cases where the relay coil requires 100 mA or less and the input current is 2 milliamps or more. The resistor value (R) is.... -
This logic probe uses a single CMOS IC and shows three logic conditions, High, Low and Pulsing. In addition if the probe input is neither hi or low (the high impedance state of tri-output logic ic`s) then no LED`s will light. Power from the logic probe is.... -
The following instructions will allow you to build a practical test tool for troubleshooting and analyzing digital and microcontroller circuits. The complete Assembly and Instruction Manual can be downloaded from the the following web link: Don`s Projects.... -
This logic probe can be selected to operate on TTL or CMOS logic levels, depending on switch S1. A string of resistors associated with switch S1 sets the threshold levels for a window comparator comprising IC1a and IC1b. Depending on whether the level.... -
In ladder logic symbolism, an electromechanical relay coil is shown as a circle, and the contact(s) actuated by the coil as two parallel lines, almost like a capacitor symbol. Given this knowledge, interpret the following ladder logic diagram: How do we know.... -
Two-transistor Darlington connection provides very high input impedance that does not load logic circuit being monitored, while driving LED that glows when logic 1 is present at input.-F. M. Mims, Computer Circuits for Experimenters, Radio Shack, Fort Worth,.... -
Five uses tri-state audio logic pen (CD4066, 555) circuit diagram is shown as the chart. The circuit is mainly composed of the multivibrator, the four-way switch CD4066 (IC1) and the gate circuit composed of some RC components. Multivibrator is composed of.... -
Neon lamps serve as diode gates and indicate positions and moves on game board. Thyratron-relay com bination serves as memory, while relays referee sequence to prevent two successive moves by either player. -C. E. Hendrix and R. B. Purcell, Neon Lamp Logic.... -
Figure 1 is AND gate logic circuit. Its logic expression is P=A, Figure B has 2 photodiodes in series. When input logic level A=1, B=1, output P=1. In a similar way, itcan form Or gate, NAND gate, NOR gate and some other logic circuits. As shown in figure 2,.... -
Logic power control of analog regulator can be useful in application where a digital circuit/controller need to control power source, such as in EEPROM programmer or other power controls. This is a circuit provide ON-OFF control for 78xx regulator using.... -
The above picture is audio logic level probe circuit, which is composed of voltage comparator, multivibrator, and piezoelectric ceramics HTD etc. The latter two constitute audio circuit and the audio frequency is used to assess the TTL or COMOS instrument s.... -
The figure shows the schematic for a versatile logic probe. The zener diode clamps the input signal just above the TTL inverter`s 2.2-V trigger voltage. Zener diode D1 can be left out if the probe is going to be used only on TTL circuits. The logic probe is.... -
This mini Logic analyzer is a tool for you to watch on LCD the logic transitions 0 or 1 of a digital data signal. A digital data signal can be found on the output pin of TSOP-1730 Infrared Receiver, on the Transmit and reveive pins of MAX-232 chip (RS-232),.... -
Logic probe is circuit that indicates the logic state of the node of any TTL logic circuit. It will work if we must supply the probe with the same power of.... -
Ideally, any testing equipment will not draw any current from the device under test. This ideal condition can be approximated by designing a testing device.... -
This is a coincidence detector circuit. This circuit is very useful for monitoring complex logic circuits. This circuit has two inputs, A and B. if A and B are.... -
This is a set of plans for an inexpensive, high performance digital logic probe that you can build in a few hours. It is small enough to use a plastic ball-point pen as a chassis, giving it a personalized touch and added style. The main advantage of this....
New Circuits
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This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of.... -
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is.... -
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to.... -
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This.... -
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the.... -
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,.... -
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the.... -
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power.... -
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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