Hi All,
Looking around to design a simple transistor assisted zener wide range voltage regulator capable of 10-60VDC @ 60mA for example, I started by trying the simple circuit below however, the output voltage is not exactly the same as the zener diode used due to vbe drops across 2 transistor I guess. Some may say increase the zener to compensate which is one way but just not happy with this circuit (will be last resort).
I came across a board that has a wide range voltage input so I tried to reverse engineer the circuit and I kind of think I have got the circuit right but it is not working for some reason. Also the circuit is markedly different to all the other circuits such as above as it uses an NPN & a PNP transistor, whereas all the other circuits such as above use a pair of NPN only. I have tried simulating the circuit in Multisim and it seems to work perfectly but when I make one on a vero or bread board it doesn’t work – it just outputs the same input voltage on its output!
Q3 as far as I can ID from marking looks PNP. Q2 possibly BCV47 NPN.
I would appreciate any help on this.
Thanks
Looking around to design a simple transistor assisted zener wide range voltage regulator capable of 10-60VDC @ 60mA for example, I started by trying the simple circuit below however, the output voltage is not exactly the same as the zener diode used due to vbe drops across 2 transistor I guess. Some may say increase the zener to compensate which is one way but just not happy with this circuit (will be last resort).
I came across a board that has a wide range voltage input so I tried to reverse engineer the circuit and I kind of think I have got the circuit right but it is not working for some reason. Also the circuit is markedly different to all the other circuits such as above as it uses an NPN & a PNP transistor, whereas all the other circuits such as above use a pair of NPN only. I have tried simulating the circuit in Multisim and it seems to work perfectly but when I make one on a vero or bread board it doesn’t work – it just outputs the same input voltage on its output!
Q3 as far as I can ID from marking looks PNP. Q2 possibly BCV47 NPN.
I would appreciate any help on this.
Thanks