Hello, everyone.

I started a project where I use a UDN2981 in order to activate some 24v valves. When I put the input in high, I get the 24v at the output; the problem is that when the input is low, I get around 8v at the output. I tried with a pull down resistor at the input, but it doesn't change anything. So, how can I fix that problem? Any suggestions?

Hope you can help.

Thank you a lot in advance!

 

Hello, everyone.

I started a project where I use a UDN2981 in order to activate some 24v valves. When I put the input in high, I get the 24v at the output; the problem is that when the input is low, I get around 8v at the output. I tried with a pull down resistor at the input, but it doesn't change anything. So, how can I fix that problem? Any suggestions?

Hope you can help.

Thank you a lot in advance!

How are you measuring the low output? With the load, or no load?

 

No load. I'm currently just testing in order to install it when I'm sure it's working. Could that be the cause for the voltage at the output?

 

You have to measure it with a load, with a high impedance meter you are going to measure an unreliable reading through the IC.
Use a a resistor in place of the valve if you want to test it.
Max.

 

I did a quick test with a load, and it's 0v now. Never thought my problem was so silly haha! Thank you very much!!!