The SN54/74LS90, SN54/74LS92 and SN54/74LS93 are high-speed. 4-bit ripple type counters partitioned into two sections. Each counter has a di- vide-by-two. The 74LS90 is a simple counter, i.e. it can count from 0 to 9 cyclically in its natural mode. It counts the input pulses and the output is received as a 4-bit binary. 74LS90N Datasheet, 74LS90N PDF, 74LS90N Data sheet, 74LS90N manual, 74LS90N pdf, 74LS90N, datenblatt, Electronics 74LS90N, alldatasheet, free.
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Discussion in ‘ Homework Help ‘ started by Random3sMar 3, Mar 3, 1. Jul 30, 38 0. As part of a project I am building a 74LS90 divide by 10 counter, with a clock input from a timer at 1Hz. I have built the circuit just like the circuit diagram in the link below. The Qa input is supposed to toggle each clock cycle, but if I use a logic probe to check this it remains low; same results if I use a led.
I’ve reproduced this on 2 differing IC’s. Mar 3, 2.
Oct 2, 5, 1, Download the data sheet for the 74LS90, and check the actual operation of the device against the tutorial schematic. The tutorial could have it wired wrong.
Lots of circuits on the Internet are crap. Verify that your clock source is really generating a clean clock pulse that meets the 74ls90m input specs, especially Vil and Vih see the data sheet.
Mar 3, 3. 744ls90n connected a DMM to check the voltage of the timer, when I connected the leads between pin 3 output and ground the circuit works Qa output led cycles between high and low. I’ve checked all ground connections again, but I still cannot find a reason why it behaves like this? Mar 3, 4.
74LS90 Datasheet(PDF) – Motorola, Inc
What is your Vcc voltage? Mar 3, 5. Mar 3, 6. Maybe the low out of the datahseet not low enough? Slow it way down by changing the timing capacitor, and measure the low period of the clock with your DMM. Mar 3, 7. Mar 3, 8.
74LS90 Decade counter
Oct 2, 17, 5, Mar 3, 9. Jun 22, 7, 1, What happens if you disconnect the output and pulse the counter manually with clocks? Mar 3, Apr 26, 3, 1, Post your schematic The same with a photo of your mod 10 circuit. Decade Counter Posted by schaab18 in forum: Decade counter Posted by gonks in forum: Decade Counter Posted by swinny in forum: You May Also Like: How to Reduce Power Eatasheet with Clock Gating This article will discuss the basic concepts of clock gating and how it can be used to reduce the power consumption of synchronous digital systems.
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