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μPC1237 based 2 channel speaker protector

When working with an expensive speaker system, speaker protector is an essential item to avoid any damages to speakers. In this project, we build a low-cost speaker protector by using NEC's μPC1237 IC. The circuit in this project is based on μPC1237 datasheet and it is specifically modified to work with 24V AC power source and with the 24V relay.

Prototype version of μPC1237 - 2 channel speaker protector system.

PCB design of this project is limit to 90mm × 43mm and based on through-hole components. Depending on the supplied voltage and relay, the value of R7 resistor is needed to be changed. The specified value in the schematic is for 24V AC power source and for Omron 24V G2R-2 relay. Start-up delay of this unit can be adjusted by changing the values of R5 and C5.

Schematic and PCB design files of this project are available to download at google drive.

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