Electronic load, need some help

Thread Starter

hejiang666666

Joined Jun 10, 2013
9
Dear all

I have already built an electronic load circuit, unfortunately, the voltage source V1 cannot supply any voltage to the Mosfet. Only the gate of Mosfet has voltage about 10V. So anyone can give me suggestions ? Many thanks

P.S. the op-amp I use is op37, and the voltage source itself is good.
 

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Ramussons

Joined May 3, 2013
797
Dear all

I have already built an electronic load circuit, unfortunately, the voltage source V1 cannot supply any voltage to the Mosfet. Only the gate of Mosfet has voltage about 10V. So anyone can give me suggestions ? Many thanks

P.S. the op-amp I use is op37, and the voltage source itself is good.
Your OpAmp power supply V5 is wrong - change the polarity.

Ramesh
 

LDC3

Joined Apr 27, 2013
920
Your question is unclear (to me). What do you want to know?
A second power supply?
Why there is no voltage across R6?
 

crutschow

Joined Mar 14, 2008
23,378
Post your simulation results. My simulation of your circuit works properly.

Note that if you apply a -5V input with a +5V MOSFET supply the circuit will be saturated (maximum current) and the loop will not be controlling the current.


Edit: Since the value of V5 is defined as a negative voltage, your power connections are correct as you show.
 

Thread Starter

hejiang666666

Joined Jun 10, 2013
9
Post your simulation results. My simulation of your circuit works properly.

Note that if you apply a -5V input with a +5V MOSFET supply the circuit will be saturated (maximum current) and the loop will not be controlling the current.


Edit: Since the value of V5 is defined as a negative voltage, your power connections are correct as you show.
Hi, this is the simulation, the blue line is voltage at gate, and the green one is at source of mosfet.
another pic is the practical measurements, green is input, yellow is voltage at gate. The source and drain is zero
 

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