Go Down

Topic: TIP102 vs TIP120? (Read 2736 times) previous topic - next topic

nw44414x

Are these transistors interchangeable?  I am trying to drive a relay from a digital out on the Arduino.

Thanks in advance!


nw44414x

The short answer is yes.  And I found the data sheets on my own.... they just don't mean anything to me.  It might as well be written in hieroglyphics.

KG2

The TIP102 has a Vceo "collector to emitter breakdown voltage" of 100 VDC as aposed to 60 Volts for the TIP120.  thats pretty much the only major difference.  switching anything under 40 Volts, i would just use what ever you find easiest to get your hands on.

David

KG2

Also, do you really need a Darlington transistor? any relay that requires less than 200 mA can be driven with an ordinary GP "general purpose" NPN like a 2N2222 or a 2N4401.  look for the Hfe specification on the transistor data sheet.  Hfe is the DC current gain.  A transistor with a minimum Hfe of 80 will draw less than 2.5 mA from the pin of the micro controller while driving a relay coil that needs 200 mA to close.  The TIP102 has a  minimum Hfe of over 1000 and would close a relay that required over 2 amps without drawing 2 mA from the micro controller pin.

nw44414x

El cheapo relays that I had laying around were 9V.  5V signal from arduino to Tip120 to switch the 9V for the relay. I'd have bought 5v relays if r$ had them in stock.

Go Up
 


Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

Arduino
via Egeo 16
Torino, 10131
Italy