OR Logic Gate

The OR logic gate has an output that is only low if all of the inputs are low. If 1 or more inputs are high, then that sets the output high.

74HC32 Quad 2 input OR Gate 7432 IC demo circuit for learning electronics shorts 70
74HC32 Quad 2 input OR Gate 7432 IC demo circuit for learning electronics shorts 70

The 7432 integrated circuit (IC) has 4 (quad) OR gates in it with 2 inputs each. As always, remember that you have to power the IC, even though many schematics won’t show the gate being powered.

In the demonstration schematic, I used a trimpot for an adjustable voltage, and a jumper as a makeshift single pole, double throw (SPDT) switch to give input signals. Neither way is a good for giving a signal to the inputs in a practical circuit, but they should help you understand the IC better since you have total control of them.

LEDs helps you observe what the output is doing. If you put a blue LED between the positive supply (+5V in this diagram) and the output, then the blue LED will light up when the output is low. It will be close to 0 volts while low.

Putting a red LED between the output and 0V ground, means that the red LED will light up when the output is high. The output will be close to +5V while high in this circuit.

I recommend getting at least one 7400 series high speed CMOS (74HCxx) integrated circuit kit, to make prototype circuits. Two kits is probably better if you will make a lot of circuits, because static electricity and miswiring can fry 7400 series ICs relatively easily. Affiliate link ads are added below.



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