This circuit is from Mullard 1969 documentation. The circuit operates at a relatively high supply voltage and has a 10 Vpp output. The transistors are of the time, but admit equivalents.
Suggested by an old American documentation the circuit below keeps a battery charged and at the...
This bargraph circuit is from an ancient American documentation. It indicates the charge state of...
This 1967 Electronics World circuit is suitable for frequencies up to 1 MHz. The setting applies...