Copyright Graham Knott 1999
| I am often asked for the
circuit of a pulse counter.
Well here is one which counts from zero to 9. Three stages can be cascaded to count up to 999. Pins 2 and 3 of all the 7490's must be linked together. The circuit can be driven from any device which provides a pulse output. Note that the reset switch is a "push to break" not a "push to make. The seven 330 ohm resistors can be obtained in a single IC package. |
Copyright Graham Knott 1999