3 Op-Amp Differential Instrumentation Amp
This is the best Instrumentation OpAmp, Great
CMRR, ensure supply has no ripple and keep analog
and digital grounds separate. Ri can be replaced
with a trimpot and resistor to alter gain. Connect
a preset ends to pins 1 and 8 and preset wiper to
VCC for Offset Null when high gains are
The Input zeners and diodes form a protective
clamp for all voltages above VCC-VDD. If supply is
changed to +12 -12 change zeners to 12V zeners.
Use similar Zeners at output to protect Output
from being zapped by overvoltages or high energy -
voltage*frequency transients. Add plastic
capacitors across Rf for damping AC operation or
ripple. Also avoid floating inputs by providing a
Vout = (Vp - Vn) * (2Rf+Ri)/Ri
Interactive Tutorials using Virtual Electronic
Instrumentation Differential Amplifier using Three
Op-Amps, Slide the Potentiometers and vary the mV
Source, See Output DVM. This is close to the Ideal
Instrumentation Amp, High Z and Excellent CMRR.
Slide the Potentiometers just like you would operate
a Sliding Control. Drag the Knob on Pot to increase
or decrease the resistance. The Resistance is shown
is blue letters and dynamically alters value as you
slide the pot.
The mV Source is varied by just moving mouse pointer
over the two buttons, no clicking. This reduces
finger strain and also you have a long lasting
mouse. The mV buttons are special, the variation
picks up speed if you let the mouse pointer remain
on the button. This is Ramp-up and Ramp-down. This
enables you to set it faster with just two buttons.
Finally you have a DVM a Digital Volt Meter that
just Displays the Voltage at any Point, this readout
value has to be noted down.
Use the "iframe" part in this
Instrumentation Amp xml code