Simple OR Gate.

161

03:29:30

Simple OR Gate with LED.

Shows the working of an OR gate with a 5v source.

I used 2 pulldown resistors to give the OR gate the LOW input when the switches are open, otherwhise they would be floating and weird things can happen.

Such as the OR gate detecting a high input when floating, making the LED turn on even when the switches are open.

The OR gate OUTPUT turns HIGH when "at least" 1 of the INPUTS is HIGH.
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Please bare in mind (altough not showing here) that besides the INPUT and OUTPUT pins the OR gate also has VDD (5Volt) and VSS (Ground) pins which need to be connected to 5 Volts and GROUND.

This OR gate would have 5 pins.
1 VDD (5volts)
2 VSS (Ground)
3 Input pin.
4 Input pin
5 Output pin.

The OR gates come in a variety of "packages" (ic's). For example a OR Gate with 3 or 4 INPUTS.
There are also IC'S with 2 or more OR Gates on 1 IC.

published 11 years ago

mrbronz

11 years ago

Well that dont work does it! It should work when one or the other switch are on. If one of the switches are turned off on this circuit then it just stops all together

bhargav132

11 years ago

It js not 0R gate it is AND gate

Sine_eyed

11 years ago

It's an OR gate, but logic gates won't work like this in real life either- you wouldn't place a switch on an input like this, to just turn off a part of the chip! Logic Low is not the same as off. Let's see if you can get it working..

adwaitforit

11 years ago

Its workimg as an AND gate...

hikernl

11 years ago

Hahaha it was indeed working as a AND gate, I think this is exactly what Sine_eyed ment. When turning off the switches, the gates would be floating an so there is no LOW. Connecting the two leads of the gate to LOW with pull-down resistors solved the problem.

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