Bilateral current source 2 (CB20819E)

We found this circuit in an American publication from the 1980s. Equivalent modern operational amplifiers can be used.

Precision PWM Generator (CB21335E)
This circuit was obtained from an Electronic Design from the 90's. The circuit generates signals at a...
Two-tone generator (CB24577E)
This simple Hartley circuit can generate two tones depending on the adjustment of the trimpots. The...
DC Motor Control (CB24872E)
Using the CMOS 4046 IC this motor control was found in November 1984 Radio Electronics magazine. The...