555 Timer Trouble

[DumbKid]

Hi,

I recently tried to interface a 555 timer to a 4-bit up/down binary counter. I used a java calculator with circuit to design a frequency output of 2Hz(60% duty cycle). I etched the board and soldered all components. The counter wasn't functioning. I hooked up my scope to pin 3 and ground. There was no wave. Is there any suggestings? Should I get a better schematic and attach a schmitt trigger to pin 3 for a clean square wave?
Thanks very much! [sig][/sig]

 

[raje9999]

hi,

working with 555 is a fun , send yr schematic , i will fix it.

 

[aizul]

hi..

 

[Warpdrive]

I assume you want an astable (free oscillating) 555 circuit. If so, the best astable 555 design is found on the Texas Instruments' 555 data sheet (see

http://www.ti.com

and search for '555')...

After reviewing the TI design, you should understand that Rb should be less than Ra for the 555 to oscillate. It also helps to choose a small capacitor (0.01-0.5 uF range). Since all you want to do is drive a counter, the "ON" duty cycle should be between 10%-40%, with edge triggered counters pulse width is not important.

Hope this helps.

-- Warpdrive.

 

Have you tried to OHM out your board to see if possibly you have a short on your etched board ?????

have you tried to bread board you circuit first and also have you shorted pin 2 to pin 6???????

 

[day]

I need to make a calcultaor quick!! help!!!
dorilla@hotmail.com