Fixed Current Sources

100

01:11:46

"From datasheet this circuit should work, but everycircuit have with that problems.
This circuit should have ability to use many transistors, and each of them should suply this same curent no mather what what resistance have load."
Update: Now is working, I should add a switch to disconect power source from op-amp. 

published 7 years ago

hurz

7 years ago

So what is the current as value from the “datasheet“ and why datasheet? Datasheets normaly for components and not complete circuits. Maybe you mean application note?

maxim251

7 years ago

@hurz I want try use opamp for mirroring curent, I did Curent mirror in my last circuit, using only transistors. This circuit should output curent for led diode. Resistor 100ohm is a base. If I corectly this circuit understand...

hurz

7 years ago

Your reference voltage is 3V while supply is 5V which is a voltage drop of 2V across 2kOhm results in 1mA current which is to low for a 20mA LED. Anyway, EC does have problems in simulating such circuits with feedback. Place at least a switch to the power supply. There are more tricks, lets see. Anyway, what is this “datasheet“?????????

hurz

7 years ago

Check this http://everycircuit.com/circuit/6665836713738240

maxim251

7 years ago

@hurz http://www.ti.com/lit/ds/symlink/lm158-n.pdf I use this datasheet. Page 20. I will be happy if You help me with that.

maxim251

7 years ago

@hurz. Now I did corections and is working as I before expected. Thank You.

hurz

7 years ago

Potis do have 3 terminals and it makes sense to connect them all.

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