# can opamp work this way ??

by XuFyaN
Tags: opamp, work
 P: 50 can opamp work this way ..? when i input 2volts the output is 4volts , when i input 5 volts the output is 25 volts in simple words can opamp takes the square of input signals ?? is it possible ? i know how it work as differentiator, integrator, Summing amp but what about squaring ?
 P: 5,462 To obtain squares and square roots you need a four quadrant multiplier, such as the MC 1494. There is an analog solution using the square law characteritic of diodes or FETs but they are tricky to set up.
 P: 50 can you please help about using diodes for squaring and square rooting ? what technique we use for squaring ? like if we Apply n volts the output must b n*n or simply sum of n times , like if we apply 5 volts the output must be 5+5+5+5+5
P: 4,667

## can opamp work this way ??

Review the circuit in

http://www.analog.com/library/analog...f/pdf/19_1.pdf

The transistors are working in essentially the transdiode configuration, because they give superior diode lograrithmic performance than real diodes. Look at the equations Eq (1) thru (6). The (kT/q) log function is the ideal diode I-V response.

Bob S
Mentor
P: 37,668
 Quote by XuFyaN can opamp work this way ..? when i input 2volts the output is 4volts , when i input 5 volts the output is 25 volts in simple words can opamp takes the square of input signals ?? is it possible ? i know how it work as differentiator, integrator, Summing amp but what about squaring ?
Are you constrained to using opamps? Can you use an ADC + Microcontroller + DAC instead?

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