This circuit with zener diodes was found in documentation from the 90s. The zener diodes determine the lighting point of the LEDs. The circuit is for 12 V automotive batteries.
This flasher was found in an old Hands On, but uses common components. The optocoupler can be...
This circuit with output powers of 2 to 3 W depending on the power supply was found in the...
The L3 coil is what basically determines the resonant frequency, around 1 MHz, in this oscillator found...