Find the output of the following logical circuit

Thread Starter

Arsalan Shahid

Joined Aug 29, 2016
Find the output of the logical circuit, given that logic integrated circuit treats +9V as 1 and <9V as 0.

I'm unable to figure out what is happening at the left hand side of the circuit.

Any help will be much appreciated.

Thanks in advance.



Joined Jun 4, 2014
I take it this is homework as this circuit does nothing. Weird!
As the battery on the left is 6V then anywhere in that resistor network cannot be more than 6V. The three op-amps are wirde as voltage followers, so the outputs also cannot be more than 6V. So those three inputs to the logic network must be less than 6V and so can only be understood as logic '0'.


Joined Aug 21, 2008
Since the output is binary, you have a 50% chance of getting it right by just guessing.

To start, can you calculate the voltages at all of the comparator inputs? It should be easy to find the states of their outputs from that.


Joined Mar 31, 2012
Are you sure those are 6 Ω and 3 Ω resistors?

Strictly speaking, it doesn't matter (in light of the issues mentioned by AlbertHall).