How to use MOSFET for Hide Side Switching

 

I've crafted a circuit designed for high-voltage (up to 100V) and high-current (up to 33.6A) applications, specifically for switching loads on the high side. The carefully selected P-Channel MOSFET, Q1, boasts low ON resistance. To safeguard against exceeding the maximum gate-source voltage (VGS), I've incorporated R1 and R2. Another option involves including a Zener diode across the Gate and Source. In addition, a small signal N-Channel MOSFET, Q2, effectively controls the ON/OFF switching of the N-Channel MOSFET. When the ON/OFF control is low, Q2 remains OFF. Conversely, when it's high, Q2 activates, thereby reducing the P-Channel gate voltage via R2 and effectively limiting the current.

Bi-directional Logic Level Shifter

VGS (th) = 1.3 V (Threshold Voltage)
Input = 0V ; VGS > VGS(th) ; FET = ON ; Output = 0V
Input = 3.3V ; VGS < VGS(th) ; FET = OFF ; Output = 5V

A simulation of the above circuit can be seen in the YouTube video link.

Buzzer Control

Simple Buzzer Control Circuit



This is a simple buzzer control circuit with one resistor and  FET. The circuit is suitable for magnetic buzzer indicators.