A simple CD4033 & 7-segment LED display tester with selectable input power supply inputs.

The clock input is manual with a simple pushbutton, no external clock circuit is needed. This tool is configured to provide ripple blanking, meaning if there is no digit from the counter, it will blank the LED instead of showing zero or a leading zero when testing two ICs. Lamp Test is also a feature of the tool to test the LED displays. And there is a Clock Inhibit switch to simple turn on or off the clock input. The Reset button resets the IC to indicate blank displays.

This tool can be powered with a standard wall adapter of 5, 9, or 12 volts. When 9 or 12 volts in selected, a manual selection, a 5 volt regulator provides the clean 5 volts.

ZIF sockets are used to hold the ICs and machined pin female headers are used as sockets for the 7-segment displays.