Driving 12v SevSeg from Arduino 5v

Using Arduino LEDs and Multiplexing
1

hi guys, i'm having problems with driving the 12v SevSeg (10pin sevseg. 3pin for digit[cathode] 7pin for segments[anode]

I'm currently using this library GitHub - DeanIsMe/SevSeg: Seven segment display controller library for Arduino

and was able to do it small scale

both are common cathode and i'm having problem with driving the 12v SevSeg

  1. do i need some kind of drivers for this?
  2. can i just use a NPN transistor on the segment pins and PNP on the digit pins
2

  1. yes, without you will damage your Arduino.

  2. It top switching 12v you need both. If bottom switching you need just an NPN. For example if you have a common anode just connect it to 12 V with the cathode connected to the resistor and then to the collector, emitter to ground and base through a resistor to Arduino output.

3

Grumpy_Mike:

  1. yes, without you will damage your Arduino.

  2. It top switching 12v you need both. If bottom switching you need just an NPN. For example if you have a common anode just connect it to 12 V with the cathode connected to the resistor and then to the collector, emitter to ground and base through a resistor to Arduino output.

Thank you kind sir.. can you guide me to a driver so i can do my research and test on it.. I'm kinda new to electronics... thank you so much

4

Only if you can tell me what sort of seven segment display you have? Is it common cathode or common anode?

5

@Grumpy_Mike

It's a 12v sevseg common cathode.. i tested by directly connecting the segment pins to positive and a digit pin to negative.

6

i tested by directly connecting the segment pins to positive and a digit pin to negative.

Don’t do that you will damage your digital pin as it puts 12 V on it when it is off which is way over the Vcc + 0.5V limit.

It's a 12v sevseg common cathode.

That is probably the worst way round. You need an NPN and PNP to drive each segment.

Comon Cathode 12V driver.jpg
Comon Cathode 12V driver.jpg578×637 31.2 KB

Comon Cathode 12V driver.jpg
Comon Cathode 12V driver.jpg578×637 31.2 KB

7

Grumpy_Mike:
Don’t do that you will damage your digital pin as it puts 12 V on it when it is off which is way over the Vcc + 0.5V limit.

That is probably the worst way round. You need an NPN and PNP to drive each segment.

Comon Cathode 12V driver.jpg
Comon Cathode 12V driver.jpg578×637 31.2 KB

i hooked it to a 12v power supply. hehe. thanks for this mike... i learned something new today.

and out of curiosity, how should i connect things with a common anode 12v sevseg?

8

how should i connect things with a common anode 12v sevseg?

The same almost. The single NPN pulls down the segments and the segment driver circuit is connected to the common anode.