ELECTRONICS - [counter device] - [page 1/3]

Counter Device

General Overview

The purpose of this circuit is to measure the time that a certain contact is open. This time must be displayed in seconds on a few 7-segment displays (at least four, so there is a minimal range of one hour/3600 seconds).

Measurement Methods

The device should be able to handle a certain number of mesurement methods. These are:

measure 5V TTL signals
measure CMOS signals (may vary in voltage
measure if there is contact/no contact