100 Hz Second Order High Pass Filter (CB25815E)

This filter with the 741 op amp was found in the February 1995 Electronics Now magazine. The power supply must be dual.

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....