A collection of seven voltage regulator diode application circuits

tiankai001

A collection of seven voltage regulator diode application circuits [Copy link]

1. Analysis of typical DC voltage stabilization circuit with Zener diode Zener diode is mainly used to form DC voltage stabilization circuit, which has simple structure and average voltage stabilization performance. The following figure shows a typical DC voltage stabilization circuit composed of Zener diode. In the circuit, VZ1 is a Zener diode and R1 is a current limiting protection resistor of VZ1. The unstabilized DC working voltage is added to the voltage stabilizing diode through R1. Since the working voltage is much larger than the voltage stabilizing value of VZ1, VZ1 enters the working state, and a stable DC voltage is obtained at both ends, which serves as the output voltage of the voltage stabilizing circuit. When the DC working voltage fluctuates, the current flowing through R1 and VZ1 fluctuates accordingly. Since the voltage stabilizing diode VZ1 remains unchanged, the voltage drop of the fluctuating DC voltage is on the resistor R1.

tiankai001

2. Zener diode in electronic filter The figure below shows the application circuit of Zener diode in electronic filter. In the circuit, VZ1 is Zener diode, VT1 is electronic filter tube, C1 is VT1 base filter capacitor, and R1 is VT1 bias resistor. After the voltage-stabilizing diode is turned on, the base voltage of VT1 is stabilized at 13V. According to the characteristic that the junction voltage of the transistor emitter junction remains basically unchanged after the conduction, the DC output voltage of the emitter of VT1 is also stable at this time, thus achieving the purpose of stabilizing the output voltage.

tiankai001

3. Surge protection circuit composed of voltage-stabilizing diode The figure below shows a surge protection circuit composed of voltage-stabilizing diode. In the circuit, K1 is a relay, VZ1 is a voltage-stabilizing diode, R1 is a current-limiting protection resistor, and RL is a load resistor. When there is no surge in the operating voltage, the operating voltage is not high enough to make the Zener diode VZ1 conduct. At this time, VZ1 is cut off, no current flows through relay K1, and the contacts of K1 remain on. The operating voltage supplies power to the load RL normally through the relay contacts. When the working voltage surges, the voltage rises and the voltage zener diode VZ1 is turned on. At this time, current flows through the relay K1, and the contacts of K1 are disconnected. The voltage cannot supply power to the load RL through the relay contacts, thus protecting the load RL.

tiankai001

4. Overvoltage protection circuit composed of voltage zener diode The figure below shows an overvoltage protection circuit composed of voltage zener diode. In the circuit, VZ1 is the voltage zener diode, VT1 is the control tube, and +115V is the main working voltage. Resistors R1 and R2 form a voltage-dividing circuit for 115V DC working voltage. The divided voltage is added to the base of VT1 through the Zener diode VZ1. When the 115V voltage is normal, the divided voltage between R1 and R2 is not enough to make the Zener diode conduct. At this time, the base voltage of VT1 is 0, VT1 is cut off, and its collector is at a high level. At this time, the standby protection circuit does not work and the circuit works normally. When the voltage is higher than 115V, the voltage divided by R1 and R2 is enough to turn on the voltage zener diode VZ1. At this time, VT1 is saturated and turned on, and its collector is at a low level. The circuit enters the standby protection state through the control of the standby control line.

tiankai001

6. Limiting circuit composed of voltage-stabilizing diode The figure below shows the limiting circuit composed of voltage-stabilizing diode. In the circuit, A1 and A2 are integrated circuits, and VZ1 and VZ2 are voltage-stabilizing diodes. The output signal from pin 1 of integrated circuit A1 is added to pin 1 of integrated circuit A2 through R1. When the amplitude of the output signal of pin 1 of integrated circuit A1 does not exceed the voltage regulation value of VZ1, this signal is completely added to pin 1 of integrated circuit A2; when the amplitude of the output signal of pin 1 of integrated circuit A1 exceeds the voltage regulation value of VZ1, the excess amplitude makes VZ1 conduct, and the maximum value of the signal amplitude is limited, achieving the purpose of amplitude limitation. 1) The amplitude limiting circuit composed of R2 and VZ2 has the same working principle as the circuit composed of R1 and VZ1, except that it is used to limit the amplitude of the output signal of pin 2 of integrated circuit A1. 2) R1 has the same function as R2, which is used to transmit signals between integrated circuits A1 and A2, and is also a current limiting protection resistor for VZ1 and VZ2. 3) The limiter circuit only limits the voltage that exceeds the voltage value of the Zener diode, and has no side effects on the signal voltage that is less than the voltage value of the Zener diode.

tiankai001

7. Arc suppression circuit composed of voltage zener diode The figure below shows an arc suppression circuit composed of voltage zener diode, which is usually used in some high-power electromagnetic magnet control circuits. In the circuit, VZ1 is a voltage zener diode, L1 is an inductor, R1 is a current limiting protection resistor, and S1 is a power switch. The working principle of this circuit is: when the power switch S1 is turned from on to off, the directional electromotive force generated at both ends of the inductor L1 is positive at the top and negative at the bottom. This reverse electromotive force is very large and is added to both ends of the voltage regulator diode VZ1 through R1 to make it conductive, thereby releasing the reverse electromotive force energy and preventing a large electromotive force from being generated on the switch S1, thereby preventing an arc from being generated and achieving the purpose of arc extinguishing. When the power switch S1 is turned on normally, the DC voltage added to VZ1 through R1 is not large enough to turn on VZ1, so VZ1 is in the cut-off state and does not affect the normal operation of the circuit.

tiankai001

5. Overvoltage protection circuit in power amplifier The figure below shows an overvoltage protection circuit in a power amplifier. In the circuit, VZ1 and VZ2 are protection diodes, which are voltage regulator diodes with relatively high voltage regulation. VT1 and VT2 are two output tubes in the power amplifier. 1) When the DC working voltage is normal: the voltage regulator diodes VZ1 and VZ2 are not conducting, which is equivalent to an open circuit, and have no effect on the normal operation of the power amplifier. 2) Circuit analysis during protection: When the DC voltage rises abnormally, the voltage-stabilizing diodes VZ1 and VZ2 will break down, clamping the DC working voltage between the collector and emitter of VT1 and VT2 tubes, so that the DC working voltage between the collector and emitter of VT1 and VT2 tubes will not increase further, thus achieving the purpose of protecting the output tube of the power amplifier.

lindeijun

Thank you for sharing!!!