This simple low power triplicator was found in 90’s American documentation. The diodes can be general purpose types and the frequency is determined by the RC network of the 555.
This circuit adds a beep to turn on with car flashers that do not have this feature. A 47 ohm to...
Depending on the value of C1, this oscillator can produce signals of up to 1 MHz. For a capacitor of 10...
This commercial circuit, sold under the designation H531 in Japan in the 1960s, used three...