This benchtop equipment was found in Radio Electronics magazine from April 1960. The two double valve circuit is powered from mains power.
The circuit shown in the figure consists of a low voltage dropout (LDO) regulator for 200 mA using...
Found in Radio Electronics from the 90s, this circuit has a power given by the output amplifier. The...
Many reed switches can be wired in series to perform na efficient alarm as shoen in the figure....