# Zero-span circuits?

1. Apr 5, 2011

### bos1234

What exactly is a zero-span circuit? How does it work?

2. Apr 5, 2011

### Staff: Mentor

Do you mean like gain and offset adjustments in an amplifier?

What is the context of your question? Or did you just hear the term someplace and were wondering what it meant?

3. Apr 5, 2011

### bos1234

For example like this

Input range 100mV to 400mV and output Range is -10V to 10V. And it says design a zero-span ckt,

edit:changed input range from 40mV(mistake) to 400mV

Last edited: Apr 6, 2011
4. Apr 5, 2011

### vk6kro

I haven't heard the trem "zero-span" before, but it probably means two different adjustments.

They want 100 mV (DC) to produce -10 volts out and 40 mV (DC) to produce +10 Volts out.

So, the input signal varies by -60 mV and the output signal varies by +20 Volts so you can work out the gain (and whether the output is inverted).

Also, a DC offset would be involved.

5. Apr 6, 2011

### bos1234

ok. I am to design a ckt. where the inputs range from 100mV to 400mV and the output ranges from -10V to 10V. I have attached my workings and a final design of the op amp ckt. Am I on the right track?

6. Apr 6, 2011

### vk6kro

The input voltages were 100 mV and 40 mV.

I think you are using 400 mV.

I got a gain of 333.

7. Apr 6, 2011

### bos1234

Sorry that should be 400mV. I have edited the post above.

Last edited: Apr 6, 2011
8. Apr 6, 2011

### vk6kro

100 mV gives -10 V out
400 mV gives +10 V out

So, should you be using an inverting amplifier?