Overvoltage and undervoltage protection circuit diagram | High and low voltage protection circuit diagram Using LM358
clear: both; text-align: center;"> Voltage fluctuations and power cuts adversely affect various electrical appliances such as Tv, music system, refrigerator, etc. Here is a simple and inexpensive circuit using opamp Lm358 to disconnect the equipment during high and low voltage. We can also use LM324 to design this circuit by using only the two op amps out of the four. We can also design a high low voltage cut out using 741 op amp. In this case, we have to use two 741 ics. You will need: Transformer: 0-18v or 9-0-9v, 300mA or above Resistors : R1 – 10K, 1/4W R2 – 50K (preset) R3 – 50K (preset) R4 – 33K, 1/4W R5,R6 – 4.7K, 1/4W R7 – 100K, 1/4W R8 – 2.2K, 1/4W R9 – 100K, 1/4W Diode: D1 – 6.2V, 1/2W Zener D2,D3 – IN4148 D4 – IN4007 DB1 – Bridge Rectifier – DB107 Capacitor: C1 – 470uF, 40V C2 – 0.1uF, Ceramic Led (5mm or 3mm) L1 – Green L2 – Yellow L3 – Red Q1 – s8050 Transistor RY1 – 12V Relay Ic U1 – 7812 U2 – LM358 High and ...