Found in a 1970s RCA documentation, this circuit generates signals according to the component values. A table is given next to the diagram.
This circuit was obtained in the manual of the used integrated circuit. Equivalents may be used...
This source whose voltage depends only on the zener diode used, can supply currents up to about 3 A....
This highly sensitive circuit was found in a 1967 General Electric SCR manual. Equivalent...