30 MHz Amplifier (CB5939E)

This low noise circuit was obtained from a 1980s US RF publication. Transistors used are uncommon today and the gain is 19 dB..

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1 kHz Low Pass Filter LM3900 (CB14188E)
The circuit shown below is from the National Semiconductor's 1994 Linear Applications Handbook. The...
Metronome with the CA3130 (CB12478E)
This metronome was found in a 1979 publication, but it can be assembled more easily with the BC548...
Symmetrical 5 V power supply (CB24712E)
This circuit for a maximum current of 1 A is the most common version that uses the 78 and 7905...