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Voltage controlled current source

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sudiipta

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Hi, I have made one vccs on breadboard and which is working. But I have a problem with the circuit. Actually I want to source and sink +/- 100 mAmp through a load of 500 ohm. My circuit is unable to draw that current. How can I modify for my requirement? I am attaching the circuit.
https://obrazki.elektroda.pl/2_1344599918.png

Thanks
 

0.1A*500E will be 50V. In this type of configuration the output across load cannot swing more than the applied vcon. Transistor emitter output will not be more than +/-12v as the opamp can swing only till +/-12v(ve=vb-0.7).
 

Do you think only high voltage opamp such as OPA445 will serve the purpose? Or can you suggest some alternate approach for the current source?
chaitanya2k6er said:
0.1A*500E will be 50V. In this type of configuration the output across load cannot swing more than the applied vcon. Transistor emitter output will not be more than +/-12v as the opamp can swing only till +/-12v(ve=vb-0.7).
Click to expand...
 

sudiipta said:
Do you think only high voltage opamp such as OPA445 will serve the purpose?
Click to expand...
In general, yes. But even OPA445 will stand only ±45V .


sudiipta said:
Or can you suggest some alternate approach for the current source?
Click to expand...

Try something like the "inverted Howland Current Source" seekIC,com.jpg **broken link removed**.

For ±50V power supplies, two 47V Zener diodes should do the job (I'd hope).
 

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