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### Author Topic: Counter 7 Segment circuit help  (Read 7094 times)

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#### Mosquito

• Guest
##### Counter 7 Segment circuit help
« on: March 25, 2008, 15:40:28 PM »
I have the attached circuit and i wonder: The 330 Ohm resistors that i have chosen for the limiting current from IC to 7 seg is enough or should i choose a bigger resisotors?

#### FrED

• Guest
##### Re: Counter 7 Segment circuit help
« Reply #1 on: March 28, 2008, 00:13:02 AM »
For led i know 1K is ok. Is this like leds?

#### kam

• Administrator
• Hero Member
• Posts: 1849
##### Re: Counter 7 Segment circuit help
« Reply #2 on: March 28, 2008, 00:40:16 AM »
You need 30mA
You can calculate the resistance using the ohms law. You do not provide the voltage so i cannot help you more.

Get more info here: http://www.pcbheaven.com/theory/ohm/

And calculate it here: http://www.pcbheaven.com/handbook/calculus/index.php?calc=ohm

#### FelIX

• Guest
##### Re: Counter 7 Segment circuit help
« Reply #3 on: March 28, 2008, 01:29:53 AM »
For led i know 1K is ok. Is this like leds?

Lower than 1K. They will be not bright enough.

#### Erkeli

• Guest
##### Re: Counter 7 Segment circuit help
« Reply #4 on: March 28, 2008, 09:49:01 AM »
Depends on the voltage

#### Mosquito

• Guest
##### Re: Counter 7 Segment circuit help
« Reply #5 on: April 02, 2008, 22:48:47 PM »
it is 5 volts

#### kam

• Administrator
• Hero Member
• Posts: 1849
##### Re: Counter 7 Segment circuit help
« Reply #6 on: April 03, 2008, 08:13:51 AM »
R=U/I = 5/0.02 = 250

330 ohm is ok.

#### Mosquito

• Guest
##### Re: Counter 7 Segment circuit help
« Reply #7 on: April 07, 2008, 19:10:06 PM »
Okey dokey!

BTW: I love Dr.Calculus!