I have 3 of these, they are some kind if isolator.

It looks like this but has the part number "Yaohua DY12S12-1W"

http://ictoic.cn.china.cn/supply/2010967557.html

I need to find an equivalent part, that's easier to obtain.

 

My guess is it is a DC-to-DC converter, possibly +12V to -12V.

 

it's a DC-DC converter, it isolates the power supply from whatever it's powering.
and it's positive output.

I think it's called a DC-DC isolator or something. I'm going from memory but I think it optically isolates the two sides, or has two small windings inside.

It was for an voltage display that required power, but couldn't receive power from the source it was measuring. if it didn't have a second source, then this component was needed.

So what would be an acceptable part to replace this.

 

I think I found a replacement by accident.

These are Isolated DC-DC converters.

Can find a couple of other different ones on digikey for $3 - $60ea

 

I think I found a replacement by accident.
These are Isolated DC-DC converters.
Can find a couple of other different ones on digikey for $3 - $60ea

That is a DC to DC Isolator, you can see the similar product as this.