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.

RF amplifier (CB20045E)
The transistors are 2N918, 2N3464 and other RF equivalents of the time for Q1. For Q2, 2N3399, 2N2894...
Sensitive triac controller (CB7864E)
This circuit, which can be used as a shield, was found in a 90s Electronic Design. The circuit...
Transistorized Push-Pull Intercom (CB11210E)
This interesting intercom circuit was obtained from an Argentine publication from the 1970s....