Voltage to Current Converter

An operational Amplifier IC LM741 used as a voltage to current. It is used for signal transmission of instrumentation like RTD THEROCOUPLE single from long distance to control circuits. Two type of current converter are.,

  • Floating load Voltage to Current converter.
  • Ground load Voltage to Current converter.

Floating load V to I converters are used as low voltage ac and dc voltmeters, diode,LED and zener diode testers. Voltage  to current converters Grounded load are used in testing such devices as zener and LED  forming a ground load.
             Float Load V to I converter Circuit.
 V-I
Formula: Floating load:- V – I converter.
Vin = Vid + Vf  where Vid  is input difference voltage and Vf is the feedback voltage
But Vid = 0
Vin = Vf = R1RL
IL = Vin/RL
 

  • Give input voltage to the non-inverting terminal of 741 and vary the input voltage.
  • Measure the ammeter reading for various values of input voltage.

Ground load V to I converter.
 
 
v to i2
Formula: Ground load V – I converter.
I1+I2=IL
(Vin-V1)/R+(Vo-V1)/R=IL
Vin+Vo-2Vi=ILR
Since op-amp is non inverting
Gain=1+(R/R)=2
Vo=2Vi
Vin=Vo-Vo+ILR
IL=Vin/R
 

  • First switch on the op-amp dual power supply.
  • Give input voltage to the non-inverting terminal of 741 and vary the input voltage.
  • Measure the ammeter reading for various values of input voltage
Comments(2)
  1. CHINMAI P April 14, 2016
  2. Ramesh July 24, 2016

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