Transistors OR Gate

111

01:16:15

If one of the switches or both are on, the circuit is closed and the LED is on. The switches are the inputs and the LED is the output.

published 5 years ago

cadder

5 years ago

This is actually NOR gate

PrathikP

5 years ago

No, it's an OR gate. The LED lights up based on OR logic. If both the switches are open, the LED is off. If either one or both of the switches are closed, the LED turns ON. This is the definition of an OR logic circuit.

PrathikP

5 years ago

It's fair to say that this isn't a stand alone OR GATE, but this circuit definitely follows OR logic

cadder

5 years ago

If both switches are open both transistors goes cut-off and you will read Logic High from transistors collectors as output. If both or any switch is off then transistor goes saturation this case collectors output will be Vce(sat) = 0.2V approximately which means logic low.

PrathikP

5 years ago

Cadder, please try to understand what the output is. The output is the LED and not the collector of the circuit. If the LED glows, the output is considered ON. Please read the circuit discription. It is clear that the switches are the input and the LED is the output. I mentioned this in my previous comments

PrathikP

5 years ago

Switch open = logic 0, switch closed = logic 1. LED OFF = Logic 0 and LED ON = Logic 1. It is simple.

2ctiby

5 years ago

cadder clearly stated that if the output is called the collector voltage, then that is a NOR. PrathikP has no right to say that the output must only be the current through the LED. Either can be considered, as long as we clearly state which output we are talking about. Logic gates however, do not normally refer to a "current" as being the output.

2ctiby

5 years ago

Likewise, we need to declare what we regard as "high" for an input manual switch ... some may call a closed manual switch high whilst others would say that a closed manual switch shows low volts when closed. ... At least here we are all agreeing on a closed manual switch being declared as "high". Declaring our ins and outs is important especially when we are using manual switches and lamps etc rather than high/low obvious digital voltage inputs/outputs.

fatcat2

5 years ago

Yup. This is a NOR gate. Check the voltage at the output.

PrathikP

5 years ago

And the output is the LED. donno how many more time I have to say it

PrathikP

5 years ago

@fatcat2, I think it's you who needs to check. And please read my comments properly. I have explained what the circuit author should have explained in the discription.

fatcat2

5 years ago

Oh yeah

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