I have the schematic for an 8 channel 24V to 5V optocoupler board I purchased. It uses the EL817.
My input is an open collector input pulled up with 10K to 5V.
I can’t drive it to gnd to trigger my input. It only goes down to 1.79V.
I would like to upload the schematic and my load if I can.
- Is your board something like this? i.imgur.com/dYahUoa.jpeg. You might like to show us a photo or the link to your board. – tlfong01 3 mins ago Edit
- Ah, it a a little bit confusing. You seem to have mixed up input with output. I guess the following is what you are doing: (1) The board consists of 8 channels, each of which is EL817 based. (2) Each input is open collector with 10K pulled up to 5V. (3) Output is perhaps open collector and also pulled up to 24V (not sure), (4) Not clear why you cannot “drive” input to ground. Perhaps you can give us a link to your board, or show us a photo. Cheers. – tlfong01 1 min ago Edit