Constant current (or voltage) source WITHOUT semiconductors?

[NuLED]

Hello - Is there a way to provide constant current (or voltage) without using ICs or even transistors?

I would expect a lot of energy lost through heat, from analog current and voltage division (or maybe not?) but what about the feedback system to maintain the constant level?

Thanks.

 

[Bluejets]

Look at the older DC generator systems on automotive charging circuits.

 

[Alec_t]

Saturable reactor / magnetic amplifier?

 

[Ratch]

Hello - Is there a way to provide constant current (or voltage) without using ICs or even transistors?

I would expect a lot of energy lost through heat, from analog current and voltage division (or maybe not?) but what about the feedback system to maintain the constant level?

Thanks.

Sure, it is easy to do. Suppose you want to build a 10 ma constant current DC current source. Find a 100 volt DC supply. Then insert a 10k resistor in series with the voltage.source. Now you have a 10 ma current source that will use 100 volts to assure that 10 ma exists. If that is not enough, then higher voltages and resistances can be used.

Ratch

 

[BobK]

A battery makes a pretty good constant voltage source.

Bob

 

[(*steve*)]

you could also build a circuit with valves!