It will work fine for 24v. I'm using them myself for this purpose with the 
same circuit board, design and components on both 24 and 12 volts systems.

The only thing that varies between the machines fitted with them is the 
input voltage (12 or 24v) and the output devices (12 volt are relays, 24 
volt are pneumatic solenoids).

Dom
----- Original Message ----- 
From: "alan smith" <micro_eng2@yahoo.com>
To: "Microcontroller discussion list - Public." <piclist@mit.edu>
Sent: Thursday, July 30, 2009 2:28 PM
Subject: [EE] ULN2803A


>
> sometimes you simply stare at the data sheet...thinking...hmmm...doenst 
> make sense but it should.  So for example I was looking at the datasheet 
> for the ULN2803 located at
>
> http://www.st.com/stonline/books/pdf/docs/1536.pdf
>
>>From what I gather, the different flavors are discussing the input control 
>>voltage, not whats being switched?  Client is using the 2803A, being 
>>driven from a PIC and is using it to switch 12V relays. Now they want to 
>>change to 24V relays...the part is rated on the transistors to 50V so 
>>shouldnt be a problem...right?  I just wanted to make sure I was reading 
>>the datasheet correctly, for those who have used this part in the past
>
>
>
> -- 
> http://www.piclist.com PIC/SX FAQ & list archive
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