This simple power supply, which is equivalent to 2 AAA or AA batteries, was found in an Elektor from the 90's. The transformer has a 4.5 V secondary with a current of 50 mA or more.
This relay driver or shield was found in a 1960 Sylvania transistor manual. The circuit is for...
This circuit is from an 80's documentation. The circuit makes use of a component of the era, the...
This modulated siren has frequency adjustment and modulation in the trimpots. For 220V use 1N4007 as...