How to adjust the amplitude of the square wave?

Thread Starter

circuitnaiver

Joined Oct 1, 2021
22
Hello, guys,

I have a circuit design to output the +6V and -12V square wave with the input 0V and 6V. Vout is connected to the oscliscope.

1633114168055.png

One of my friends designed this circuit. But it does not work in the simulation. Can anyone help me out with this?

Thank you~
 

crutschow

Joined Mar 14, 2008
28,161
Are you constrained to 6V and -12V supplies or can they be higher voltages?

What should be the output voltage for 0V input?
 
Last edited:

crutschow

Joined Mar 14, 2008
28,161
But the ideal case is that we only single supply, like 6V directly from the input source without any added power supply.
That's not ideal, that's impossible.
How do you expect to get -12V from a +6V supply.
An opamp can only output no more that its supply voltages.

If this is school work, why are you using someone else's design?
Shouldn't you be doing your own?

I have a design that does what you want using only 4 resistors and the opamp, but you need to demonstrate some understanding of op amps circuits before I will post that.
 
Last edited:

Thread Starter

circuitnaiver

Joined Oct 1, 2021
22
That's not ideal, that's impossible.
How do you expect to get -12V from a +6V supply.
An opamp can only output no more that its supply voltages.

If this is school work, why are you using someone else's design?
Shouldn't you be doing your own?

I have a design that does what you want using only 4 resistors and the opamp, but you need to demonstrate some understanding of op amps circuits before I will post that.
I think I understand how it works. The Op amp can work as a comparator by comparing one analog voltage level with another analog voltage level. Something work as follows:
1633118461359.png
 

dcbingaman

Joined Jun 30, 2021
495
Hello, guys,

I have a circuit design to output the +6V and -12V square wave with the input 0V and 6V. Vout is connected to the oscliscope.

View attachment 249231

One of my friends designed this circuit. But it does not work in the simulation. Can anyone help me out with this?

Thank you~
You can accomplish the goal also with 2 BJT transistors and a few resistors. Because this is homework, can't provide solution but something to think about.
 
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