The device presented here can be used to count events as well as to measure frequencies and times. Most of it is built from discrete HC (high speed CMOS) logic and to be honest, if I needed to build such a device again, I would not build it as presented here but integrate things into a CPLD or a microcontroller instead. However, it was instructive not to do so and maybe it is interesting for other people as well (for what reason ever).
- Frequency measurement from 0.1Hz to ≥10MHz; gate times of 0.1, 1 and 10 seconds
- Time measurement 0.001ms to 10000s (time clock 1MHz and 1kHz): measuring L/H time or 1, 10 or 100 complete pulses or time between input A and B transition
- 5-digit LED display with display hold
- CMOS-compatible Schmitt-trigger inputs with over- and under-voltage protection
Frequency Counter - [Link]