Project Basics

Current Buffer

The ULN2001A, ULN2002A, ULN2003 and ULN2004A are high voltage, high current darlington PIN CONNECTION arrays each containing seven open collector dar- lington pairs with common emitters. Each channel rated at 500mA and can withstand peak currents of 600ma.

WHERE TO USE:

These versatile devices are useful for driving a wide range of loads including solenoids, relays DC motors, LED displays filament lamps, thermal print- heads and high power buffers in the situations when the input signal is not providing enough currents. E.g. we need to drive a relay or DC motor according to the signal given by some IC.

HOW TO USE:

Suppose we need to drive DC motor and the motor needs a specific amount of current. It’s in the range of 30-100 mA. But such high currents cannot be delivered by simple ICs or parallel port etc. Hence we need a current buffer for that. So we select Uln-2003 in this case.

The pin connection of ULN 2003 is as follow:

The ULN 2003 is an inversion buffer and hence output is taken from pin 9 and the output pin.

If we are driving motor according to the signal from some IC which is not able to provide enough current, then

  • Firstly we input that signal to one of the 7 input pins of ULN 2003, say pin 1.
  • Then output I taken from the Pin 9 and the corresponding output pin i.e. pin 16 as shown below:
  • We also connect a high current power source of appropriate voltage between pin 9 and pin 8.

HOW IT WORKS:

When the input signal to the IC ULN 2003 is HIGH, then the output of the IC at the corresponding output pin is LOW. But if input signal to the IC ULN 2003 is LOW, then the output of the IC at the corresponding output pin is HIGH.

Hence in the above circuit, when input at pin 1 is HIGH, then the DC motor would start running as at the positive terminal of motor we have a HIGH and at the negative terminal we have a LOW (pin 16). But if input signal is LOW, the DC motor would not work as we have HIGH at both terminals of the motor.

Input at Pin 1Output at Pin 16Motor
LOWHIGHDOESN’T WORK
HIGHLOWRUNS

LIMITATION: Using this kind of buffer we can’t drive the DC motor in both directions without using much extra circuitry. For performing all 3 functions on motor i.e. run clockwise, run anti-clockwise and stop, we can use another IC L293D which is a bi-directional buffer.

34 Replies to “Current Buffer

  1. время работы налоговой инспекции
    в пушкино московской области работа транспорта в москве ночью как расширить работу дизайнера
    работа бухгалтером оператором в
    воронеже работа для пенсионеров в костроме на авито

  2. Pingback: pgroyalbet
  3. к чему сниться что меня воруют лучший расклад таро
    на отношения с мужчиной индивидуальный гороскоп по дате рождения
    бесплатно
    к чему снится месячные если задержка если приснилось что фотографируешься

  4. битва экстрасенсов рустам что нельзя готовить на
    новый год 2024, что нельзя готовить на год
    дракона к чему снятся игральные карты девушке
    магия цвета ставрополь улица 50 лет влксм к
    чему снится пьяный друг мужа

  5. 12-ші үйдің билеушісі күн 12-де, ақ орданы билеген ұрыс хан 1368 69 жылдары асфиксия кезіндегі
    алғашқы көмек, тұншығу ұстамасы кезіндегі алғашқы көмек ауылдың түні текст, түңгі клуб скачать
    версаль вашингтон конференциясы, вашингтон конференциясы қатыспаған мемлекет

  6. шудын бойында песня, шудын бойында турикше скачать что значит джай
    на казахском, разговор на казахском
    қытай ақшасы теңге, қытай курс валюта қатаңдығы 100 н/м серіппеге бекітілген, қатаңдығы 20 н/м

  7. цена химчистки салона авто, химчистка салона авто с выездом отбасы банк застройщики, отбасы банк ипотека вторичное
    жилье банк центркредит карта карта, карта карта бцк как снять
    деньги майкрософт турция, microsoft 365 казахстан

  8. Pingback: Skywind Slots
  9. Pingback: โคมไฟ

Leave a Reply

Your email address will not be published. Required fields are marked *