220V AC siren circuit
220V AC siren circuit See Other projects in : Alarm systems • Mini Projects And: Alarm sounds , Sirens Posted by admin - May 16, 2014 at 12:33 am This circuit is a simple siren circuit that use 220V AC as power supply. It is small size and use a piezo speaker cause use low power and saving. How it works This circuit is shown as Figure 1 which we use power source by reducing AC-voltage of 220 volts down by the resistors-R1, R2 ; the capacitor-C1 act as coupling AC-voltage. Secondly, the current will rectifier into DC voltage by diode bridge D1-D4. And there is C2 function to filter steady DC current. Figure 1 The simple 220V AC siren circuit. The some voltage will flow to emitter lead of Q5 and other will is sent to R3-R6 to reduce voltage to ZD1 before, which it will maintain the steady (DC) current regulated supply at about 9.1 volts. The capacitor-C3 will smooth or filter the pulsating voltage from a power supply into direct current. To begin with press