This is the fire alarm circuit which use LDR to sense the smoke from the fire, so it can be used to detect any dark smoke. With the onset of summer season, possibilities of fire accidents […]
Category: Security
Heat Detector + Siren
This is the diagram of heat detector circuit which already integrated with siren circuit in the output. This circuit applies a complementary pair comprising NPN metallic transistor T1 (BC109) and PNP germanium transistor T2 (AC188) to […]
LPG Gas Leakage Sensor Alarm
This is the schematic diagram of LPG gas leakage sensor alarm. The circuit operates off a 9V PP3 battery. Zener diode ZD1 is applied to convert 9V into 5V DC to drive the gas sensor module. […]