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.
When we say to an astable multivibrator circuit. People will think to use IC-555. But this time, it is recommended CD4047 circuit