Electronic engine revolution counter calibration circuit - uses power supply frequency pulse generator or battery-powered amplifier oscillator

摘要

A calibration circuit for an electronic revolution counter used with combustion engines is designed to enable revolution counter mfr. using mechanical assembly techniques independent of the measurement device and to ensure that calibration can be simply achieved irrespective of the number of cylinders of the engine. The revolution counter receives pulses derived from engine ignition pulses and has an adjustable counter time. Instead of the device producing counter pulses from ignition pulse, a calibration pulse generator using the power supply frequency as a standard may be connected to the revolution counter. Alternatively, a two-stage amplifier supplied from the car battery may be connected to the counter by a bridge connection.