DCA55 question

[adapt]

i just got one of these, and after measuring a ton of shit, i decided to measure a few transistors from a smallbear kit, that came pre-measured. one of them said hfe = 80 and leakage of 125.

well, when i measured it with the DCA, it came up hfe = 98 and leakage = 0.98.

should i be concerned? am i using this thing wrong? it sure doesnt seem like there's any room for error.

[JaviCAP]

Your fingers make the hfe to raise :) It sounds funny, but it's true, even the room temperature affects the HFE and the leakage.

For a "perfect" measure, check the trannie 10 minutes after you engage it to the Peak, you'll see how the HFE reads lower than the first time.

J.

[adapt]

haha yeah, i figured that out last night, even putting your fingers on it for like 3 seconds drops the hfe to like, 8. pretty crazy. but the leakage is still pretty different, would temperature affect the leakage also?

[rocket88]

i've had that happen a few times too adapt, nothing to worry about at all. what i usually do when testing all my Ge transistors is i set them up to be tested, making sure i can grab the leads without them touching each other, and let them sit for like 5-10min. i just grab each lead of the transistor with the DCA55 without touching the transistor at all to help prevent heating the transistor and throwing off the hfe.

[iggy]

room temp will effect the reading a lot as well. and i have found the more leakage a transistor has the more it is effected. I try to get measurements between 72 -75 degrees F. Testing at 80-85 F can easily push the gains up 10 hfe or more