Thank you mos57. Forgive me as I am learning about transistors at this time. Would the K version be better because it has upper Vcbo and Veco than the base version? For instance my amp has the 2SC2362 as differential pairs. Would using a K version be advantageous?
Last edited:
The markings on those are odd. The ones I have bought are laser etched, not printed like yours are. These are either extremely old, or re-marked from something else. The first ones you show seem to be missing a letter code for breakdown voltage - maybe that's normal, but I haven't ever seen one of these without a complete date code or hFE rating. I'm really not too sure about the first ones. If I had received ones like in your second picture, I'd be checking beta first off.
I have attached the data sheet for this part. I hope this helps you out.
-Chris
I have attached the data sheet for this part. I hope this helps you out.
-Chris
Thanks for the response Chris. Below is a picture of the existing transistors. The labeling does look more like a laser engraving on those however the codes are relatively the same as the 1st in my picture above. I am still searching for 20 or so to be able to match them with the curve tracer.
Okay, those match in appearance. They must have been manufactured way back in time. That's ooold stock!
Once you have matched pairs, make sure you have them in thermal contact and held together. A match doesn't work if they are allowed to vary in temperature independently. Also, you don't need a curve tracer to do this. Just use a jig and run the expected tail current through them. Look for a balanced condition for your match. If you want to go all out, try a couple different tail current levels. Personally, I find that a curve tracer is good for checking a wide range of operating conditions. Remember that the operating point in this circuit is pretty much fixed when using a matched pair. The operation of a long tailed pair will linearise their transfer characteristic. With newer production parts, you will have more matches simply because they have the production process under better control. The parts will be more alike as long as you are picking from the same batch. Wouldn't it be nice if you could buy from the same wafer?
-Chris
Once you have matched pairs, make sure you have them in thermal contact and held together. A match doesn't work if they are allowed to vary in temperature independently. Also, you don't need a curve tracer to do this. Just use a jig and run the expected tail current through them. Look for a balanced condition for your match. If you want to go all out, try a couple different tail current levels. Personally, I find that a curve tracer is good for checking a wide range of operating conditions. Remember that the operating point in this circuit is pretty much fixed when using a matched pair. The operation of a long tailed pair will linearise their transfer characteristic. With newer production parts, you will have more matches simply because they have the production process under better control. The parts will be more alike as long as you are picking from the same batch. Wouldn't it be nice if you could buy from the same wafer?
-Chris
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.