modified 6 years ago

Name of topology

00:34:59

I've seen it in amplifier circuits.
Can someone tell me the name of it? 

published 6 years ago

lenzrulz

6 years ago

Interesting...👍

AmplifierFAN

6 years ago

Thanks!

Robert_Kidd

6 years ago

Constant current source. As bottom transistor base voltage rises and causes it’s collector voltage to fall, the base voltage of top transistor falls reducing current flow through it, hence opposing voltage increase on bottom transistor base. This results in equilibrium.

Robert_Kidd

6 years ago

Right hand circuit is PNP version of same.

Robert_Kidd

6 years ago

I think some adjustments need to be made to give better performance.

hurz

6 years ago

Its calles "constant current sink" lower resistor is the shunt to monitor the current and when it get to high and drops 700mV the lower transistor get active and take the bias current of the upper transistor away. So its clear the shunt resistor must be much smaller while the upper resistor can be increased to bias the upper transistor. Forget this PNP version before you have not understand the NPN current sink. Here an circuit example for 20mA current sink http://everycircuit.com/circuit/5794461834280960

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