Are generic Ebay component testers any good?

[Onemangang]

Hi.

I was looking for a diy curve tracer kit for bjt, jfets, mosfets, diodes... Not many of those as diy:/

But I found a million different component testers like these.
Are they any good?

LCR-TC1 Colorful Displays Multi-functional TFT Backlight Transistor Tester Diode | eBay
LCR-T4 Mega328 Transistor Tester Diode Triode Capacitance ESR Meter NPN/PNP UP | eBay

They can measure transistors hfe and polarity, resistors, caps, inductors and more.
There are many different versions

Regards

 

[JonSnell Electronic]

The two you have listed are basically the same apart from a box on one of them. They work very well.

 

[Vovk Z]

As I see - they are not curve tracers. Just multy-testers.

 

[Refugee1]

The first one listed has more inside the box.
It includes a TV remote control tester and USB charged internal battery. Neither of these come with the bare board.
It is well worth the extra money.

 

[Onemangang]

Hi

Thank you all. I ordered two of them to help me educate my neighbour.
Turns out he's a geek/nerd about hifi just like me

 

[dynoPort]

when I test film capacitors with one of these it reads 2-3 ohms that can't be right?

 

[Onemangang]

Hi dynoPort

What information does it show other than the ohm's ? Does it say it is a capacitor?
For a film capacitor to go to a few ohms, I guess it would be a big value cap, and the measuring frequence would be quite high.

A little math…

The impedance can be calculated using this formula R = 1 / ( 2 * PI * F * C )
Since we do not know F ( Frequency ) we can use what we do know. Lets say you film cap is 470nF and it's said 2-3 ohms. Then we get:

F = 1 / ( 2 * PI * 470e-09 * 3 ) -> 112.875 KHz

Is that plausible as testing frequency for such a circuit?

 

[phofman]

I recall some discussion about cap's ESR measurement by these testers where 100kHz were mentioned.

 

[Refugee1]

ESR varies with value.

 

[nigelwright7557]

The transistor testers tend to be low current so can give odd readings that you wouldn't get at normal higher "working" currents.
The market is swamped with them so you can get them for peanuts.

 

[Refugee1]

For power transistors I have a home made unit with a range of collector current settings.
Germanium transistors also don't measure well on these modern testers.