Author Topic: 15v 500mA ower supply questions  (Read 517 times)

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Offline khatusTopic starter

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15v 500mA ower supply questions
« on: August 30, 2019, 04:39:56 pm »


Hello guys, I want to know what is purpose of the transistor T3(BC547B) in this circuit. I understand it provides base current to the series pass transistor T5(2N3055). Also i want to know

1. what is the function of transistor T4(BC557B) and  T2(BC547B) and T1(BC547B)??

2. Here D1 (1w,15V) is a zener diode?



3.What is BZ1(24V) in this schematic?


 

Offline Zero999

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Re: 15v 500mA ower supply questions
« Reply #1 on: August 30, 2019, 10:08:06 pm »
T3 forms a Darlington pair, with T5

T4 compares the reference voltage set by the potentiometer with the output voltage. it's in common base configuration. It turns T2 on, when the reference is exceeded by 0.6V, thus cutting off T3.

Yes, D1 is a zener diode.

BZ1 is a buzzer, which is turned on by T1, when a the current flowing through R1 exceeds a certain threshold, set by R1.
 


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