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| Transistor Shunt Voltage Regulator |
Transistor Shunt Voltage Regulator Working is explained below,
In the transistor shunt voltage regulator shown in Figure, the regulating transistor is in shunt with the output terminals. If the output voltage Vo increases, the base-emitter junction of the transistor T1 becomes more forward biased so that its collector current increases. This collector current is the base current for the transistor T2. An increase of base current of T2 raises its collector current which is an amplified version of the collector current of T1. The collector current of T2 is the base current of the transistor T3. An enhancement of the base current of T3 increases its collector current which is a still further amplified form of its input current. An increase of the voltage V0 thus causes an increase of the collector current of T3, increasing thereby the voltage drop across the resistance R. The circuit is thus self-correcting, the increased drop across R reducing the voltage V0 which is thus stabilized. The transistor T3 has to handle a large collector current. So, it must be a power transistor.
In the transistor shunt voltage regulator shown in Figure, the regulating transistor is in shunt with the output terminals. If the output voltage Vo increases, the base-emitter junction of the transistor T1 becomes more forward biased so that its collector current increases. This collector current is the base current for the transistor T2. An increase of base current of T2 raises its collector current which is an amplified version of the collector current of T1. The collector current of T2 is the base current of the transistor T3. An enhancement of the base current of T3 increases its collector current which is a still further amplified form of its input current. An increase of the voltage V0 thus causes an increase of the collector current of T3, increasing thereby the voltage drop across the resistance R. The circuit is thus self-correcting, the increased drop across R reducing the voltage V0 which is thus stabilized. The transistor T3 has to handle a large collector current. So, it must be a power transistor.
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Power Supplies