5 LED Log Scale with U257B (CB25442E)

The circuit was found in the February 1992 Radio Electronics magazine. The scale can be changed by changing R2 and R3.

Sound Activated Relay (CB19971E)
This Vox or sound activated relay was found in an American documentation from 1975. Equivalent...
4 A 79xx Negative Current Regulator (CB15341E)
This circuit is from Motorola's Linear Interface ICs from 1993. The circuit uses a booster...
1000 second timer (CB23601E)
The existence of field effect transistors at the input of the integrated circuit (operational...