Today I would like to introduce the simple and economical simple siren circuits. It is suitable for beginners. My son will gradually build this circuit onto the PCB layout. Look at below! 4 Circuits. Read more
The Mouse and Rat repellent circuit using astable multivibrator which use sound waves or ultrasonic so it escaped away. Use transistor and piezoelectric. Read more
The cricket sound effect circuit which is an another Sound effects generator byLM324 op-amp and emit by a buzzer. And they have sound similarly the cricket Read more
Here is The 4 Sound effects generator using UM3561 and a few parts only. It can make siren, Ambulance sirens, Police car sirens, Fire truck siren and Space Read more
SEE! Simple Sine wave oscillator low frequency. Without thermistor and Incandescent lamp so very linear in transistor and zener diode circuit. Read more