2-bit decoder 7400 (CB22421E)

This circuit decodes a two-bit value into four outputs (one of four). The circuit must be powered by a voltage of 5 V.

Wireless AM Microphone (CB16392E)
This is the project found in a 1981 publication, but it is still viable. It is a simple AM...
Two Transistors T20 Radio (CB18386E)
This commercial earphone receiver was manufactured in the 1960s in Japan. It was powered by a 9 V...
Intermittent Tone Generator (CB18955E)
This circuit was found in a European publication from the 1980s. The transistors can be the BC548...