E)
This circuit uses a reversible double contact relay to obtain the trigger lock with the unijunction pulse. The relay must be of the sensitive type with at least 150 ohms of coil.
The CK722 transistor used in this circuit is one of the first commercial types in the world. The...
This automatic dimmer for incandescent lamps was found in a European publication from the 1980s. The...
This traditional doubler configuration with the 555 can be found in other articles on the author’s site....