Circuit diagrams and schematics - Electronic projects

This is Simple light sensitivity Metronome circuit. It use the transistor 2N3904 numbers and 2N3906 make to are origin frequency circuit. By the frequency in the sound from a loudspeaker will increase and is down. When lead light flasher come to near LDR within a darkroom. By resistance value of LDR be down when receive [...]

The circuit detects a sudden shadow falling on the light-sensor and sounds the bleeper when this happens. The circuit will not respond to gradual changes in brightness to avoid false alarms. The bleeper sounds for only a short time to prevent the battery running flat. Normal lighting can be used, but the circuit will work [...]