Pages: [1]   Go Down
Author Topic: Driving a transformer  (Read 317 times)
0 Members and 1 Guest are viewing this topic.
Offline Offline
Newbie
*
Karma: 0
Posts: 46
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Just wrote down a basic square wave to drive the transformer which is 230V AC input and 11V AC output.
This was a transformer extracted from a Guitar amplifier.
Connected the arduino from 11V side and expected to see at least half of the 230 V (If I'm not mistaken arduino supplies around 3V, right)

However when I touched the LED to 230 V side of the transformer, LED was barely blinking with a pale light.

What might be wrong with this ? Why the voltage drops even under the 5V when it passed through the transformer ?

Quote
 digitalWrite(led, HIGH);
  delay(20);      
  digitalWrite(led, LOW);  
  delay(20);
« Last Edit: April 13, 2013, 06:32:32 pm by zoom » Logged

Manchester (England England)
Offline Offline
Brattain Member
*****
Karma: 603
Posts: 33402
Solder is electric glue
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

DO NOT connect an arduino directly to a transformer you will damage the output pin.
The point at which damage starts to be done is 40mA. That means the transformer must have a resistance of about 125R for it to be safe.
Drive the transformer through a transistor with a diode across the coil.

Quote
If I'm not mistaken arduino supplies around 3V, right
No it normally gives a 5V output. Well it gives about the same output as the chip is powered by so a 3V3 arduino can give 3V.
Logged

Pages: [1]   Go Up
Jump to: