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.



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

Thank you~

 

Are you constrained to 6V and -12V supplies or can they be higher voltages?

What should be the output voltage for 0V input?

 

Change V2 to -6V.

 

Are you constrained to 6V and -12V supplies or can they be higher voltages?

No, higher voltage supplies can also be used. But the ideal case is that we only single supply, like 6V directly from the input source without any added power supply.

 

Can anyone explain to me the function of R11? Why do we use a 1M ohm resistor here?

 

Change V2 to -6V.

I tried, but the simulation still cannot run.

 

Can anyone explain to me the function of R11? Why do we use a 1M ohm resistor here?

Is this school work?

 

Is this school work?

Yes

 

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.

 

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:

 

The Op amp can work as a comparator

Yes, it can if you just want two output levels.
If you want the output to go to the power supply rails, then you need a rail-rail type op amp.

 

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.

 

You can accomplish the goal also with 2 BJT transistors and a few resistors.

That will give a +6V output for a 0V input and a -12V output for a +6V input?

 

That will give a +6V output for a 0V input and a -12V output for a +6V input?

Assuming we have a +6V supply and a -12V supply. I was thinking the other way around: 0V goes to -12V and +6V goes to +6V.

 

I was thinking the other way around: 0V goes to -12V and +6V goes to +6V.

Yes, I see that his original circuit uses the non-inverting input for the signal, so that would be the polarity you are thinking.