4093 Sine Square Converter (CB26335E)

Found in a Popular Electronics from the 90s, this circuit operates up to about 5 MHz input.

Drill Speed Control (CB1353E)
This simple half-wave control using an SCR, which may be TIC106, has been obtained from a US...
DC Motor Reversal with Transistors (2) (CB11602E)
I found this circuit in an English publication from 1989. This configuration can be mounted with...
TTL Output Magnetic Reader (CB14249E)
This reader with TTL logic compatible output uses an LM139 comparator. The circuit was found in...