This circuit is powered by a voltage of 4.5 V, being common in radios of the 60's. The circuit is from Mullard's transistors reference manual.
This configuration (using a logic gate with TTL compatible output) uses an amplifier transistor to obtain...
In addition to the didactic purpose, the figure circuit can also be automated. In this case, the...
The maximum time interval of this circuit depends on C1. Larger values can be used to get closer to...