This circuit was found on an 80's Ham Radio. The transistor admits equivalent. The circuit can generate 20 to 100 MHz signals operating at the fifth harmonic of the crystal.
Found in English documentation, this circuit uses a thermistor as a sensor. The trigger point is...
In the figure we have the way to implement a TTL Schmitt trigger for 60 Hz signals, obtaining...
This General Electric circuit produces pulses of light only when light stops shining on the...