Quantitative pulse generator circuit

Quantitative pulse generator circuit

Shown is a quantitative pulse generator circuit that can set the number of pulses generated. The maximum number of pulses can be set to 999 and
can be used as a signal source for a stepper motor. The circuit consists of a three-level subtraction counter , a gated oscillator and an RS flip-flop. The subtractor is selected
to preset the binary 1/N counter C182. The gated oscillator is composed of NAND gates 1 and 2, and NAND gates 3 and 4 are buffer output stages. The RS
trigger is C039.
    Since the all "0" output terminal of the ones counter lCl is connected to the PE terminal of the three-stage subtraction counter, once reset, the counter will
accept the preset number. The preset number terminal of the counter is connected to the BCD code disk switch, which can be controlled by the BCD code. Disk switch setting. At the same time, the RS flip-flop
is also reset, so that the gated oscillator cannot work and the circuit outputs a low level.
    When a start signal is added to the input terminal of the RS flip-flop, the RS flip-flop flips and the gated oscillator starts to work. The output pulse of the oscillator
is also a clock signal added to the CL terminal of IC1, causing the counter to start counting down from the preset number. When the count is reduced to 0,
a high level appears on all "o" terminals of ICI, which resets the RS trigger. , the oscillator stops oscillating and the output no longer sends pulses. In this way, each time the circuit is started
, a preset number of pulses will be emitted.