Segment counter using IC555 and IC4026

James Myers's picture


Joined: Apr 03, 2017

Replies: 1
Segment counter using IC555 and IC4026
April 4, 2017 - 7:50am

What changes to the circuit are necessary if I used a common cathode, 7 segment display with a Vf of 6.8 (instead of a regular one having Vf of 1.8)?  Thanks for any ideas.

Aswinth Raj's picture


Joined: Aug 16, 2016

Replies: 958
I doubt it would work
April 5, 2017 - 7:44am

The forward voltage drop of 6.8V is quit high for a 7-segment display, is it a dual color 7-segment display?

In that case using this circuit will be of no use to you. If you just wanna operate on mono color then I think you can try this IC because the datasheet gives a source current of 6.8mA under typical conditions. 

Just incerease your Vdd(Supply voltage) to 15V and try out the circuit. Add current limiting resistors (10K for example) initially so that we dont fry up the display.