Low-cost-frequency-counter

Posted on Feb 5, 2014

This counter uses a four-digit display, but with a flip of the range switch, it can display frequencies from 1 to 40 MHz, with a resolution of 100Hz. The MM74C926 CMOS IC contains a four-digit decimal counter that can latch a given count and then use this information to drive a 7 -segment, common-cathode multiplexed (MUX) display. The block diagram and schematic show the operation of the counter. Crystal-controlled timer U1 through U3 produces a 5-Hz square wave used for timing the frequency.

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