Simple Logic Probe
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 and therefore on, powered by the 12V supply. When a logic “high” is present at the probe, IC1a’s output goes low sending IC1b’s output high. This turns off LED1 but forward-biases (and turns on) LED2. Conversely, a logic “low” at the probe will send IC1b low, turning LED1 on and LED2 off.
Author: F. Edwards
Categories: Digital, Meter Tags: logic gate, logic probe
Logic Digital Tester by LM324
This is Logic Digital Tester Circuit. It uses the level input about 5V and use the integrated circuit LM324. Be Main Part electronics perform Drive All LED. Then use Current very low about 10mA by have potentiometer be formed fine the value threshold give just right with the level logic digital both of 3 the level that use by LED1(Green) be the level high and LED2(Red) Be the level LOW and The LED3(Yellow) be the level High IMR . The detail is other please see in the circuit please sir.
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Logic Probe by 74LS47
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 connect the “Test” wire of the probe to the desired node of the circuit that we want to check.
Source: http://www.electronics-lab.com/projects/test/020/index.html
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Categories: Circuit com, Digital Tags: digital circuit, logic probe
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