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Jun 30, 1. May 15, 68 0. I purchased a few counters and a few BCD decoders. My intent is to have the driven by a timer in monostable mode, that datasheft be switched between the Up and Down inputs a switch between Ground and Pin 2 would send a pulse to to input of either the Up or Down input of the The problem is, my circuit’s not working I’ve constructed Up-counters, using before and it’s a very easy build, however this one is proving much more difficult. It might have to do with the low-active components of the [opposed to high-active, which is when a high signal triggers the IC though i’m sure most of you knew that ].

According to the datasheet for thethe input that are not in use want to be kept high, while the few circuits i’ve seen keep them low. I’ve tried both arrangements, but to no avail. When I turn on the circuit and yes, i’m using a regulated 5V for the enture breadboard the 7-segment display I have shows “0” but does not change. Also, when i apply Ground to the ‘s Lamp Test LT pin, the 7-segment display reads “8” as it should. I know the timer works because i’ve tested it with LED’s.

It pulses at a rate of about ms High-Low as per its configuration so I doubt that it’s the problem.

That only leaves the as the culprit so basically, I probably have datashet wired incorrectly. It’s current configuration goes as follows: Pin 1 of input B 3: Pin 7 of input A 4: Pin 2 of input C 7: Pin 6 of input D 8: Carry No Connection Borrow No Connection GND via 10k resistor Here’s the datasheets for the 2 IC’s datasheet: Jun 30, 2.


Mar 24, 21, 2, Hand sketch it and scan it, you don’t need to be fancy, just 7192. Jun 30, 3. Jul 17, 22, 1, What is the part number on your timer? If it’s a BJT timer, the output may not be going high enough to be detected as a logic “1”. Jun 30, 4. Apr 20, 15, Jun 30, 5. But in the meantime, i’ll sketch this circuit, scan it and post it. I’ve 741992 that before on other threads. Perhaps that is the problem. Maybe I could test out the funtionality of the with 4 LEDs and let it count in binary, the way it was specifically meant?

Jun 30, 6. If you want to try just the ‘, use ohm resistors in series with the LED’s to limit current. Jun 30, 7.

File:74LS192 Symbol.png

Jun 30, 8. Yep, that ‘ can’t provide a reliable input to the CD If you want to try a kludge, add a 4. Jun 30, 9. Jul 1, I got it working perfectly. In fact, i’ll post a circuit diagram sometime tomorrow so no one else ever has these problems. Thanks for all the help everyone. Okay, I’m going to bed after messing around with this thing for a long time.

File:74LS192 Symbol.png

If I take the connector between Pin 3 and the Input, the clock remains the same until replaced Side Note: The Up works, the Down works; the problem is in the switching back and fourth. First, in removing the cable, evenvwhen there’s no pulse from the timer, the digit on the 7-segment displays jumps a bit i figure that’s just regular bouncing.

So I put a SPDT ON-ON switch into the circuit the connector from PIN 3 of the timer was the common and one pole connected to the Up input and the other to the Down inputbut there was still some bouncing even when there was no 741922 from the timer. Next course of action was to use 2 timers.


At first I used a dual timer just got them in the mail today but the results weren’t working i figured that i was either wiring them wrong or they were faultyso I then used to separate timers. They were working just fine I tested them and had them in monostable mode.

But when I hooked them up to the inputs one to the Up and one to the Downthe display dayasheet all haywire, as though the button was just held low, and it just kept cycling through digits. Apr 26, 3, 1, Perhaps more to the need is something like a logic simulator – http: The only think that worked was manually switching the output cable from the UP input to the DOWN input, and there was still some switch-bouncing. Google “LTSpice Download” to get there.

Lots of models and help there. CircuitMaker Student might be found out there, but it’s a dead-end product, and won’t run on Vista, and probably not on Windows 7. Cadsoft Eagle is available in a freeware mode.

(STMicroelectronics) – Synchronous Up/down Decade(,binary) Counter | eet

Pretty powerful, but you’re limited to a 3″x4″ board and just 2 layers – still, plenty for a lot of hobby projects. Nov 28, 1, I’ve noticed that you have connected 10K resistor on TTL input pins to trying datasheey pull the logic level down to low.

This might seem to work but the value is way too high for TTL. Jul 2, Up Down Counter Circuit Posted by maruf10 in forum: You May Also Like: It’s time to assemble your very own SmartBrella. We’ve rounded up some of the best ones.

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