05-13-2022 06:11 AM - edited 05-13-2022 06:12 AM
So, i built a circuit in real life with a 74ls390 and its output follows the voltage of the Vcc but when I build the same circuit on multisim, the output is always 5V regardless of Vcc voltage.
i am hoping that there are some settings that can be changed to change the output voltage of the output pins or some other decade counter IC that would change their output voltage according to Vcc of the circuit.
Solved! Go to Solution.
05-13-2022 09:02 AM
Привет, дорогой!
Идеальная модель в программе предполагает 5 вольт. Так задумали разработчики. Переключив на реальную в смешанном моделировании, теряем скорость, но получаем более реальные результаты.
05-13-2022 09:56 AM
why is it outputting negative voltage
05-13-2022 12:03 PM
In case you need my testing circuit:
05-13-2022 12:15 PM - edited 05-13-2022 12:28 PM
Обратите внимание на "землю". Нужно выставить цифровую
Во вкладке "состав модели" есть таблица выводов, куда какое питание подключать.
05-13-2022 12:41 PM
ahhhhh i see, thank you very much
05-14-2022 12:49 AM - edited 05-14-2022 12:54 AM
"Спасибо" в карман не положишь, а звезда хоть правильный путь укажет в нашем грешном мире 😀
Спасибо вам за оценку!
08-28-2022 07:55 AM
Hi johndoeeerae and tipa,
The logic family 74LSxxx (Low-Power Schottky) is designed for 5 V digital circuits. The absolute maximum rating for its power supply voltage is only 7 V while the recommended operating condition is Vcc = 5 V ±5% for a range of 4.75 V to 5.25 V. You are attempting to use a 9 V supply voltage for the IC and it may appear that your experiment is successful in simulation. On the other hand, if you will build the real circuit, the excessive supply voltage is very likely to cause damage to the IC.
Here are some of my recommendations so you might be able to achieve your objective:
The counters CD4029 and CD4518 are both synchronous while the 74xx390 is a ripple counter (please verify this from the datasheets to be sure). However, this difference may not be important in what you are doing.
Best regards,
G. Goodwin
08-28-2022 10:56 AM
Спасибо за уточнения!