I mean what the meter (numbers) shows. I know that the hFE checks the efficiency of the transistors and shows whether they are n-channel or p-channel.
Czy wolisz polską wersję strony elektroda?
Nie, dziękuję Przekieruj mnie tamQuote:In every PDF with the description of the transistor you will find that this parameter is very scattered for the same model, e.g. for BC548 from 110 to 800.
I checked the contact plate and it does not seem that something has been burnt, so someone has hit the stickers, because this circle is not soldered so that everything is consistent
Moderated By trymer01:Regulations, point 3.1.19 Do not send messages on archival topics if it is another question, in particular other than the questioning person. Out of respect for the questioner, create your own topic. You can only add a solution to the problem.
szyszko wrote:Hello,
IN PRACTICE I mainly use the beta-meter to pair the so-called complementary pairs of PNP and NPN with low frequency amplifiers (audio power amplifiers). Also, most often, when connecting, for example, 2-3 pieces of transistors in stabilized power supplies (increasing the output current of the stabilizer), because it significantly reduces the amount of heat power lost and causes that all heat up in the same way, because the theoretically calculated value of "equalizing" resistors it is the same for all transistors in the circuit.
Unfortunately, even with the same series / batch of the same transistors, the discrepancy of their parameters can be quite large, so if you have such a possibility, you can sort, for example, from a 100 pack 10 of those that most correspond to the values given in the manufacturer's catalog.
As professional digital beta meters are quite expensive, I personally prefer the old vg. analog (pointer) meters, which are only used to measure transistors, because it is then possible to set the most appropriate measuring range, and moreover, they can be used to measure not only hFE.
greetings
Moderated By Madrik:
3.1.19. Do not send messages on archival topics if this is another question, in particular other than the questioning person. Out of respect for the questioner, create your own topic. You can only add a solution to the problem.
TL;DR: BC548 transistors ship with hFE spanning 110–800 [Elektroda, marcinj12, post #1621116]; “hFE is the DC gain in a common-emitter system” [Elektroda, Paweł Es., post #1621119] Cheap multimeters test this gain at a fixed base current, so expect ±30 % error. Why it matters: Knowing what the meter shows helps you pick substitutes, spot faults, and avoid mis-wiring. For hobbyists repairing amps or power supplies, this FAQ explains the limits—and the tricks—of the hFE socket.
• Typical DMM test current: 0.1–1 mA base, 2–10 V across DUT [Fluke Manual]. • Catalog hFE spread for BC548 group A/B/C: 90–200 / 180–400 / 350–800 [Elektroda, jta, post #16139164] • Edge-case: Darlingtons may read >1000 or “1” (over-range) due to internal resistors [Elektroda, Konan Marian, post #1845069] • Multimeter hFE function works only for small-signal BJT, not MOSFET or JFET [Elektroda, Paweł Es., post #1621119] • A 15-€ clamp-shell meter shows ±30 % gain error versus bench curve tracer [EEVblog Bench Test].
