I have a 555 astable creating a pulse to a 4017B to anotehr 4017B then to a 4026 for 7 seg display. This is a project for a sort of bleep test.

I have my circuit all working and counting on a breadboard but when i try to join resets together things go wrong.

The astable frequency is 1hz. This goes to a 4017B which counts 6 then resets. Output 6 is connected to clock input of another 4017B which has LEDs on it and LEDs light up on each 6 count after each other. The divide by 10 output is then connected to 4026B which powers the 7 segment display.

I need to make a single reset switch so all 3 chips reset at the same time which will act as a start and reset the LED to first output and 7 seg to zero.

Hope you can help. Any questions to s_collins@blueyonder.co.uk

 

Post a circuit

 

 

I would do a synchronous circuit design. You could make counters and resets sync to your clock. Also you need current limit resistors in series with all LEDs that you are driving. SOmeone will likely post a fixed up ckt.

 

The 4017B doesn't need current limiting resistors for each LED, if you want current-limiting only one common resistor is needed since the 4017B has only one output high at a time.
With only a 9V supply, the 4017B (or any normal 4XXX IC) doesn't need even one current-limiting resistor because its output current will be only about 8mA.

 

I needd to simulate an cicuit with IC's cd4026 in multsim, but there isn't this IC in my multisim...
anybody can help-me??