Position: Index > Amplifier Circuit >

Two Op-Amp Differential Amplifier

2015-01-02 09:54  
Declaration:We aim to transmit more information by carrying articles . We will delete it soon, if we are involved in the problems of article content ,copyright or other problems.

The Input Impedance of this module is very high and is symmetric. This circuit can be used for strain gauges and for four wire measurements. If inputs are in mV use OP07. The merit is that it uses only 2 OpAmps yet has high differential Input Impedance.

The Outputs of Opamps are low impedance but still have limits they cannot drive more than a few mA of Current into the Load. If low ohmic value loads are to be applied use external transistors as amplifiers. If inputs Vn-Vp are floating Outputs may be random or Oscillating, it is good to have a bias network of 10M resistors to a potential even zero or COM this enables Vout when input floats.


Two Op-Amp Differential Amplifier

Vout = (Vp – Vn) * (Rf Ri)/Ri

Related Reading

Operational Amplifiers – non-ideal behaviorPrecision Instrumentation Amplifiers
Reprinted Url Of This Article:
http://www.electronics-circuits.com/tech/2004/10/two-op-amp-differential-amplifier/