This is many LED flasher circuit and with PCB layout using transistors astable multi vibrator as low frequency oscillator below more...[...]
If you are looking for a constant frequency generator that easy and inexpensive. Here are the transistor crystal oscillator circuit ideas. They may help you works finish. Since 30 years…
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.
Often drivers forgot to turn off lights when parking. They cannot start the machine, ran out battery. This Headlight Warning buzzer circuit can help.