XNOR circuit - Can any one build XNOR circuit

[sxy]

-CAN ANY ONE BUILD XNOR CIRCUIT
FROM XOR CIRCUIT THAT ATTACED AS A LINK BELOW?

https://falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWK0AckDMYwE4As3sA2SQgdgCYFsQqabIaBTAWiwCgA3EdQlG8vjz7kKUMbgZIG06AjYBnGsW4pcShuh5iGAMwCGAG3mMFIfITO4+5s2AsMI+oyYBOZoiBHl3FzffDwbG4Iyl7q3FoOgQDu3LyeojZhkGyxSaIhDMmpPhEWNrh2UDkFaCBk3lbSbAAu5YllpJBqVWIQzDC4pGBwYJnouOiQ5MPIYOTkhJjkhUS4UyLUPQwAJoz6AK4GNbX1lUVNLUUOIMzk0OOQIUMhpBKEYCj2Fzgo5JhdpMSYhLhqyyA1pttjlMrYLBVwcVYoczOhvLD5moUjDmrlYQgBNC4nxMXwMViUm5YehMSBSKpuGSonBdhSWmUUPCzGUTjAHqTIHcwIU-oc+OzeBg0AJSYQqHcAqt1notjtiWihmoSdSpUSQEzvEqNcy-G0YrlWgUrNiwYULGD0JSUeS0RIGCrvDbNdw0S7sqi1NrYR7wmEfaIbQHvO7AzkCXwXXjinZvAQtSMQPGcZ5ATK5cwDIwVuBtMhIGBdigyvak1jS2zoAsEHBsChsJgEGAhgKqwh65RNO3Ml8+ACgbKQXUiAxS8mK7mYM07F8BOMsKQ8H187xloQRKRMXda1K08D5UnsAmGMnkmqcqG40eEk6ckfrEV73Db7En4Mr5VmTbx8zx8c79eQiHlq1p3liVpqE+QHfuB8TJtBoLKBBGplMhzqoZSxajnA2LGnwI6WAKd7KH8+EkThzrMtGLo2EGlKkgilKtDB1jMjRX4XsySI6p+L48c+-F6ikQA

 

[sxy]

You just need to add NOT get instead the LED.

 

[sxy]

Is the attached file a correct XNOR circuit?

 

[rjenkinsgb]

No, both LEDs will be on or off at the same time.
The extra LED should be in series with the resistor on the last transistor.

The original circuit was strictly an XNOR, as the inputs were active HIGH but the LED came on with the output LOW rather than output HIGH,

 

[sxy]

Can you please draw the right schematic for xnor circuit?

 

[sxy]

Can anyone explain to me the xnor circuit that attached why there is not always the led be on;
because the current from 9V will flow through R1 to the collector of T2 and to the emitor of T2
and of course the current will flow to R2 to the base of T2 to the emitor of T2 and the current will light up led L1.
So the led should always be on.

 

[ChrisP58]

If either of the two inputs are high, then T1 will be turned on and it's collector will be at gnd. Of course, this means that there will be zero volts at R2 and the collector of T2, so no current will flow to the LED.

PS. Please add values to all components in your schematics. And mark the two inputs so they match those in your truth table.

 

[sxy]

The real reason that there will be zero volts at R2 is:
Because all the 9V is already on R1 so V=I*R no voltage left to fall on R2.

 

[sxy]

But you could also ask yourself why when both inputrs are low
all the voltage will not fall on R1,
but part of the 9V will fall on R1 and the other part will fall on R2?

 

[sxy]

Can anyone explain the xnor circuit that in the picture above?

 

[Ian Rogers]

Look to the two inputs... If both are on T3 and T4 light the LED.. If both are off T2 lights the LED as T1 is off .. If only one is on, T3 or T4 alone do not complete the circuit and T1 stops T2 from completing the circuit.

Simples

 

[sxy]

I am trying to underdtand the picture how he connected them on breadboard to form the xnor gate
Can any one draw that instead on:

https://falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWK0AckDMYwE4As3sA2SQgdgCYFsQqabIaBTAWiwCgA3EdQlG8vjz7kKUMbgZIG06AjYBnGsW4pcShuh5iGAMwCGAG3mMFIfITO4+5s2AsMI+oyYBOZoiBHl3FzffDwbG4Iyl7q3FoOgQDu3LyeojZhkGyxSaIhDMmpPhEWNrh2UDkFaCBk3lbSbAAu5YllpJBqVWIQzDC4pGBwYJnouOiQ5MPIYOTkhJjkhUS4UyLUPQwAJoz6AK4GNbX1lUVNLUUOIMzk0OOQIUMhpBKEYCj2Fzgo5JhdpMSYhLhqyyA1pttjlMrYLBVwcVYoczOhvLD5moUjDmrlYQgBNC4nxMXwMViUm5YehMSBSKpuGSonBdhSWmUUPCzGUTjAHqTIHcwIU-oc+OzeBg0AJSYQqHcAqt1notjtiWihmoSdSpUSQEzvEqNcy-G0YrlWgUrNiwYULGD0JSUeS0RIGCrvDbNdw0S7sqi1NrYR7wmEfaIbQHvO7AzkCXwXXjinZvAQtSMQPGcZ5ATK5cwDIwVuBtMhIGBdigyvak1jS2zoAsEHBsChsJgEGAhgKqwh65RNO3Ml8+ACgbKQXUiAxS8mK7mYM07F8BOMsKQ8H187xloQRKRMXda1K08D5UnsAmGMnkmqcqG40eEk6ckfrEV73Db7En4Mr5VmTbx8zx8c79eQiHlq1p3liVpqE+QHfuB8TJtBoLKBBGplMhzqoZSxajnA2LGnwI6WAKd7KH8+EkThzrMtGLo2EGlKkgilKtDB1jMjRX4XsySI6p+L48c+-F6ikQA

 

[sxy]

If only one is on, all the 9V falls on R1 so no current flows through R2 and that is the reason that T2 is off.
But I am talking about the breadboard in the picture.
How he connected all the components to form the xnor circuit.

 

[sxy]

Please draw the xnor circuit on thelink:

https://falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWK0AckDMYwE4As3sA2SQgdgCYFsQqabIaBTAWiwCgA3EdQlG8vjz7kKUMbgZIG06AjYBnGsW4pcShuh5iGAMwCGAG3mMFIfITO4+5s2AsMI+oyYBOZoiBHl3FzffDwbG4Iyl7q3FoOgQDu3LyeojZhkGyxSaIhDMmpPhEWNrh2UDkFaCBk3lbSbAAu5YllpJBqVWIQzDC4pGBwYJnouOiQ5MPIYOTkhJjkhUS4UyLUPQwAJoz6AK4GNbX1lUVNLUUOIMzk0OOQIUMhpBKEYCj2Fzgo5JhdpMSYhLhqyyA1pttjlMrYLBVwcVYoczOhvLD5moUjDmrlYQgBNC4nxMXwMViUm5YehMSBSKpuGSonBdhSWmUUPCzGUTjAHqTIHcwIU-oc+OzeBg0AJSYQqHcAqt1notjtiWihmoSdSpUSQEzvEqNcy-G0YrlWgUrNiwYULGD0JSUeS0RIGCrvDbNdw0S7sqi1NrYR7wmEfaIbQHvO7AzkCXwXXjinZvAQtSMQPGcZ5ATK5cwDIwVuBtMhIGBdigyvak1jS2zoAsEHBsChsJgEGAhgKqwh65RNO3Ml8+ACgbKQXUiAxS8mK7mYM07F8BOMsKQ8H187xloQRKRMXda1K08D5UnsAmGMnkmqcqG40eEk6ckfrEV73Db7En4Mr5VmTbx8zx8c79eQiHlq1p3liVpqE+QHfuB8TJtBoLKBBGplMhzqoZSxajnA2LGnwI6WAKd7KH8+EkThzrMtGLo2EGlKkgilKtDB1jMjRX4XsySI6p+L48c+-F6ikQA

 

[Ian Rogers]

No! I wont draw the circuit on falstad....I do not have the time..

I have assumed the breadboard circuit is the schematic shown.... Its very straight forward..

 

[sxy]

Who can draw the xnor circuit on falstad?
the schematic attached as a file.
thank you.

 

[Visitor]

Try EasyEDA. It's indeed easy to use and free

 

[JimB]

There appears to be an error in this circuit:

There is no current limiting resistor for the LED when T3 and T4 are turned on.

This configuration would be better:

Adding a resistor where I have indicated with the red "circle"

JimB

 

[sxy]

The circuit works

 

[JimB]

And what is the current through the LED when transistors T3 and T4 are turned on?

JimB