problem 0f 7490 in counting

Thread Starter

Afeesh a n

Joined Jun 12, 2009
1
hi,
i have configured a 7490 as a decade counter. but as the pulse come the counter is counting with 2 ie. 1 3 5 ......what may be the problem the pulses are coming from a monostable multivibrator with time period of .6s.so plz do suggest some idea to eliminate this.

thank u
 

SgtWookie

Joined Jul 17, 2007
22,227
Are you using bypass capacitors on both your astable multivibrator's Vcc/GND supply AND the 7490 supply pins? If not, there's a very likely cause.

Are your interconnecting traces/wires/jumpers long? Try to keep them as short as possible; long wires have a good deal of inductance, and will cause circuits to oscillate unexpectedly.
 
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