What's the difference between these two thermistors?

[paul8f]

The type required:                   NTC MF52A 10K, B=3950, 5%

The nearest match I can find:   NTC MF52D 10K, B=3950, 1%

Is the nearest match a good substitute component?
Thanks.

[Gyro]

From the look of it, the letter specifies the tolerance. In which case, the 1% part would substitute just fine for the 5% part (not the other way round of course).

It would be best to find and double check with the datasheet though.

[paul8f]

Thanks Chris,
it's been so long since I've had a chance to do anything with this repair, that I asked the wrong question!

(The A version has tin plated copper wire, while the D version has PVC insulated wire.)

So, my question should have been... what's the performance difference between the two? Or is it irrelevant for an everyday appliance that never goes over 70deg C?

[Vovk_Z]

Straight copper wire type is for PCB mounting.
PVC-isolated wires are (flexible) for mounting the thermistor somewere on a distance, for example to the heatsink.
'A' and 'D' may mean different in different manufacturers so it could be easier if you put correct datasheet at first post.

[Gyro]

Thanks Chris,
it's been so long since I've had a chance to do anything with this repair, that I asked the wrong question!

(The A version has tin plated copper wire, while the D version has PVC insulated wire.)

So, my question should have been... what's the performance difference between the two? Or is it irrelevant for an everyday appliance that never goes over 70deg C?

Ah, I wondered why there would be so many letters different between a 5% part and a 1% one.

It's hard to say without having some context of where it is to be installed, is it replacing an existing part etc. - presumably the length of the bare Tin plated copper leads would be shorter than PVC flex ones. The datasheet ought to give a maximum temperature rating for the PVC leaded part (70'C is at my personal limit of what I would be comfortable using PVC for extended periods).

The effect of the different lead types (heat conducted away from the thermistor) depends on the lead length and how well the thermistor is coupled to what it is monitoring.

Pictures would help.