Voltage Control Current Source

current source schematic voltage controlled

Hi there,

I encounter such a circuit that I find interesting.
V1 in the picture is actually adjustable voltage source and R2 acted as the Load.

My assumption is like below:
the positive current source always balance up by the negative current source when V1 is not connected(i.e. no interruption), and there is zero current flow to the RLoad.

When an amount of V1 is supplied to the circuits, "an amount" of constant current flows to the RLoad regardless what is the RLoad value.

+V1 will source current to the RLoad while -V1 will sink Current from RLoad.

My Question is, what is the V1 and ILoad relation? how do I precisely control how much current to be sink/source to the RLoad? is there any euqtions can be calculated?

Second, is there a name for this kind of methodology used?

Any opinion is welcome.

Regards,
Andy

Hi, I think the relation between V1 and ILoad is simply Ohm's law. The potential of node 2 and 3 is the same.

Well, I don't think is simply Ohm's Law because the current across the RLoad is constant regardless what the value of Rload is. The constant I is somehow determined by the V1

Iload is simply by ohms law dependent on V1 and Rl. Potentials on node 2 and 3 are equal. All load current is supplied by V1 and current generators and diodes are here just for complication of problem. When V1 is different from 0V the currents through diode branches will change for amount of Il/2 up and down depending on the polarity of V1.

well I did simulate this using multisim/electronics workbench, the suggested Ohm's Law is not really correct to reflect this circuit's operation because ILoad is porportional to V1, but ILoad has nothing to do with the RLoad, varying RLoad will have no effect on the ILoad.

So, ILoad != V1/Rload

hence, Iload = ?? * V1

?? = what? anyone ?

Please let me know if my statements are wrong.

The previous replies are correct, it is just ohm's law.

Check your simulation: perhaps you entered a resistor that's too low a value such that the current hits its maximum of the 0.5A source. The schematic as shown should work fine; just make sure you entered it properly, or post it and we'll show you what went wrong.

Try a thought experiment: if the Rload is infinite, what is the current from the V1 source (at 10V) and the current through the Rload? Then, try a second thought experiment: if the Rload is really small, like 20 ohms, again what are the currents for V1=10V?