Car alternator voltage regulator circuit

Working principle of the circuit: It consists of triode VT, zener diode VD4 and ordinary
diodes VD, ~ VD3, etc. It is actually a high-threshold transistor. Here,
VD, VD3 is the silicon diode, VD. It is a 7-9 V zener diode, which means
that only when the voltage at the P terminal is 9.5~11.5 V, the transistor VT can be turned on.
Therefore, it has strong anti-interference ability. Figure b is the pin diagram of the voltage regulator integrated circuit, and the pin symbols correspond to those in figure a. There are two models of
this circuit
: H108 type and 108 type: H108's e and b ends are internally connected with l kfl and resistor R;
while the 108 type must be connected with a 1Ω resistor between b and e when used; because the H108
type The resistance between e and b is a diffusion resistance, and its resistance value is easy to change with temperature. Therefore,
attention should be paid to the heat dissipation of H108 during use.