1. A synchronizing, pulse generator, modulator, or keyer which originates a series of continuous control pulses at an unvarying repetition rate known as the pulse-recurrence frequency.
2. A timer using electronic circuits, either tube or transistor type, to control a time period, in place of a motor or other processes.
3. A timer which has an electronic circuit to operate a relay at a predetermined interval of time after the circuit is energized, as in timing exposures for a photographic printer or in controlling an electronic generator.