K8055 voltage leakage?

Kits PC Related Projects
1

With five volts applied between grnd and clamp I read 2.20 volts when the outputs are in the low or off state. I read the applied five volts at each output in the on state.

I expected the digital outs to act as switches. I assumed I would read applied voltage in the on state but read nothing in the off or low state.

Can anyone help out me out? I am eager to learn what I’ve done incorrectly.

Thanks in adavance!

By way of an update: it struck me that I hadn’t messured each output relative to grnd before I check the switching of the applied voltage. It turns out without any voltage applied via the clamp and grnd I read 1.75 volts. Just thought I would mention it in the off chance that it wasn’t normal.

2

The digital outputs are open collector transistor outputs. It indeed is some leakage you measured from the outputs.
You have to put pull-up resistors (e.g. 4k7) between the outputs and the +5V of the external voltage source.

3

Thank you much Sir!!!

My little motor controler is working as expected now and I am very thankful for your help and the operutnity to learn!

Have a great day!