1. ITM UNIVERSE VOLTAGE TO CURRENT CONVERTER USING OP AMP
Presented by –
Vyas Devanshi
Raulji Shraddha
Branch – Electrical B
Sem 3

2. VOLTAGE TO CURRENT CONVERTER USING OP AMP
(a) VOLTAGE TO CURRENT CONVERTER USING OP AMP WITH FLOATING LOAD
(b) VOLTAGE TO CURRENT CONVERTER USING OP AMP WITH GROUNDED LOAD.

3. With Grounded Load
In this circuit,one terminal of the load is grounded and load current is controlled by an input voltage.The analysis of the circuit is accomplished by first determining the voltage V1 at the non inverting input terminal and then establishing the relationship between V1 and the load current.

4. Circuit Diagram
Fig - VOLTAGE TO CURRENT CONVERTER USING WITH GROUNDED LOAD

5. Writing KCL eqaution at node V1
I1+I2=IL
Vin-V1/R + V0-V1/R = IL
Vin V0-2V1=IL*R
Therefore,
V1=Vin+V0-IL*R/2

6. Since the op-amp is connected in the non inverting mode , the gain of the circuit is
1+R/R=2.
Then the output voltage is
V0=2V1
=Vin+V0-IL*R

7. Vin=IL*R
So IL=Vin/R
That means the load current depends on the input voltage Vin and resistor R.Notice that all resistors are equal in value.

8. The VOLTAGE TO CURRENT CONVERTER USING OP AMP shown in figure may aslo be used in testing such devices as Zeners and LEDs forming a ground load.
However the circuit will perform satisfactorily provided that load size less than or equal to R value.

9. With Floated Load
Fig shows a voltage to current converter in which load resistor RL is floating .The input voltage is applied to the non inverting input terminal and feedback voltgae across R1.

10. Circuit Diagram
Voltage to current converter with floating load

11. Writing KVL for input loop
Vin=Vid+Vf
But Vid=0Vm,since A is very large
Vin=Vf
Vin=R1*I0
I0=Vin/R1

12. Applications
The voltage to current converter can be used in such applications as low voltage dc and ac voltmeters,diode match finders,light emitting diode,LEDs,and zener diode testers.

13. Thank You