Simple constant current source

113

02:33:28

Load current is equal to the voltage at the base minus 0.6 (silicon voltage drop across the PN junction) divided by the resistor value at the emitter.

published 6 years ago

kiani

6 years ago

Good ideas are simple.. Maybe if the LED is put in base circuit 💫, it would be a clearer idea.

Bushmills

6 years ago

There's not much "constant" current - it changes when input voltage changes, and also when a resistor in series with LED changes value.

Bushmills

6 years ago

In fact does a simple resistor in series do a better job at keeping current "constant": http://everycircuit.com/circuit/5324129755201536

kiani

6 years ago

Basically Led is in wrong place..needs to be in base circuit..., can not fix current in collector when ib is changing...

PatrickRyan

6 years ago

@bushmills this isn't really made to combat big voltage fluctuations it's just to make a more efficient current source than a resistor alone would provide. This other circuit would be better if you have to combat a changing voltage. http://everycircuit.com/circuit/5559774058643456

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