Differential Amplifier - Op-Amp Circuits
This amplifies the difference between two inputs
Vp and Vn the low impedance of this configuration
is a drawback, but can be used in analog
computing. Optimum VCC VDD can be +12/-12. AC
signals common to Vp and Vn are canceled by this
Use a capacitor like 10nF plastic from pin 2 to 3
or across R2 to make circuit stable. For AC
applications use LF351 TLO71 as they have good
slew rate and also are FET inputs. For AC
applications use a capacitor (1uF) in series with
Ri to block DC Components. The Inputs have
asymmetrical input impedance this affects CMRR,
also use 1% tolerance MFR resistors for Rf and Ri.
Vout = (Vp - Vn) * (Rf/Ri)
Interactive Tutorials using Virtual Electronic
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.
Differential Amplifier is used in Analog Computation
for the Minus Operation or Subtraction. It also has
a better noise rejection and CMRR, but this one amp
differential circuit has low impedance as the
resistors network load the signal source. It is good
only for an intermediate stage.
Use the "iframe" part in this
Differential Op-Amp xml code