This circuit was found in National Semiconductor documentation from the 1990s. Operational amplifiers admit equivalents.
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...