Current Sources with NPNs

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02:00:18

The Load resistor (200 ohm) can be changed in either circuit and the load current has minimal changes on the value of the resistor.

The circuit on the left uses a zener to maintain a constant base voltage.

The right side uses a PNP transistor connected to the base of the NPN transistor. The PNP causes the NPN's emitter voltage to be equal to the inputted voltage, Vin.

The current in the load of the right side circuit can be defined as: I = Vin / 1k

published 1 year ago

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