# Display square of voltage on LED display

Discussion in 'General Electronics Chat' started by Rogare, Mar 9, 2012.

1. ### Rogare Thread Starter Member

Mar 9, 2012
78
0
Hello! I'd like to display a value on a 3 or 4 digit LED (controlled by the ICL7106 chip) that is the square of an input voltage (V) multiplied by some constant (C). In other words, the LED needs to display CV^2, where C will be around 24 and V is expected to be 05 volts. Any suggestions would be terrific.

2. ### Wendy Moderator

Mar 24, 2008
20,772
2,540
Is this going to be a modified voltmeter?

3. ### Rogare Thread Starter Member

Mar 9, 2012
78
0
In a way, I suppose, but at the end of the day it's basically being used to predict the output from another part of the circuit preemptively (so the user will know what that circuit's output will be before it arrives). Not sure if that answers your question?

4. ### Wendy Moderator

Mar 24, 2008
20,772
2,540
Simple enough, are you going to need voltmeter circuitry? Math can be done by analog computers, but you specifically mentioned a display.

5. ### Rogare Thread Starter Member

Mar 9, 2012
78
0
Thanks for the reply. No, I believe the ICL7106 chip actually covers this.

6. ### Rogare Thread Starter Member

Mar 9, 2012
78
0
OK, I think I found an answer. To square the input voltage, the AD633 chip appears to do the trick (though not terribly cheaply) and to multiply it by a constant is just a basic amp (the "multiply-by-constant" circuit here).