Problems with NTE 4017B IC

Nov 14, 2004 4 Replies

I am implementing a circuit proposed by Chris in which a 555 IC feeds its output to a decade counter, 4017B IC. The output of the 555 looks as expected, but nothing shows up at the output of the 4017. As suggested by Chris, I have CLK (pin 14) and Vss (8) at GRD, 12 VDC at Vdd (16), the output (pin 3) of the 555 going to CLKEN (13) of the 4017, and I am looking output 1 (pin 2) of the 4017. I see nothing on the scope.



Any ideas as to what may be wrong? Perhaps CLKEN should be grounded and the input put to CLK?



One thing I notice is that the NTE 4017B has a "notch" depression at one end and a "circle" depression at the other. I am assuming that pin 1 is at the end where the notch is.


TIA



Ed


Since you wonder that, I wonder why you've got it wired the way you have it? The clock input is for the clock, the CLKEN is "clock enable". The way you have it, it will never count.

Keep reset at ground, until you need to reset the counter (which in many applications will be never). Keep the clocke enable low, unless you want to disable the counting. Put the clock signal into the clock input.

Michael

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pin 14 is "positive" clock enable, or "positive" clock in (active high) pin 13 is "negative" clock enable, or "negative" clock in (active low) both are just "anded" internally, be it pin 13 is internally inverted, so both can be used as clken pin 8 as gnd pin 16 as vcc pin 15 is reset, set to gnd for operation

for correct pinout and data see

formatting link

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*ALL* input pins MUST be pulled HI or LO to make digital logic circuits work right, they do NOT default to some nominal value like HI or LO without being connected.

-Steve

-Steve Walz rstevew@armory.com ftp://ftp.armory.com/pub/user/rstevew Electronics Site!! 1000's of Files and Dirs!! With Schematics Galore!! http://www.armory.com/~rstevew or http://www.armory.com/~rstevew/Public

it?

I was just following orders, sir. :-)

I'm a novice and a member of the group (Chris) showed it that way in the diagram he kindly posted.

But, you're right. I switched them and grounded RESET and it works.

Thanks.

Ed

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