Found in an Electronic Design from 1968 this circuit generates a linear sawtooth signal modulated by an input signal. The transistors are from the era.
Found in American documentation from the 90s, this configuration detects the direction of rotation...
Circuits similar to this can be found in this section. This is from 1967 General Electric...
This circuit uses two transistors and can be powered by just two small batteries. The frequency is given...