1-Ttube reflex receiver (T1555E)

This one-tube circuit is equivalent to the previous one. We find it in a 1924 book by Gernsback, Power is made by batteries.

Lamp Driver with 40107B (CB5303E)
This circuit oscillates at a frequency of 0.5 Hz. We can find it in an American documentation from the...
Power Failure Indicator (CB6113E)
This circuit can be found in a 1970 Motorola documentation. The circuit can be implemented with general...
Divider by 5 Counter (CB25363E)
This TTL circuit was found in the December 1990 issue of Radio Electronics magazine. The circuit has...