PicSignalDetection is an automatic on/off switch designed for power amplifiers (but it is useful with other equipment as well). The circuit will switch a 230V relay if an input signal is detected. After 15 minutes without signal, it will automatically switch off the equipment again, this way preventing unnecessary use of energy. Maximum switching current is 5A, about 1000W.

Optionally, DC detection for one channel is incorporated, which can switch an amplifier output relay. With this circuit and a power amplifier circuit, an active speaker can be easily made.

Since revision 4 of the pcb, also balanced inputs are supported.