Infrared modulated transmitter (CB7247E)

This simple Philips circuit from the 1960s can use any general-purpose transistor. The signal is modulated at 2.7 kHz.

Relative impedance meter (CB7487E)
Found in a 1960 Sylvania manual, this circuit can be implemented with a modern equivalent...
Logarithmic Converter (CB19486E)
This configuration, already presented in other points of this section and website, is of a...
2 Meter Crystal Oscillator (CB4051E)
We found this precise crystal oscillator for the 144 MHz band, depending on the crystal used. The...