This circuit was published in an article in Radio Electronics magazine in October 1988. It uses components that are still common today, except for the sensor, which is a special type from that time.
The time the output is high (1) of a TLCSSB in the astable configuration depends on Ra and C. The...
The adjustment of the maximum load voltage is made in the trimpot. The circuit is from 1994...
This circuit from a 1967 documentation generates 2.5 Hz signals depending on the capacitors used,...