This little box is one version of a ubiquitous component tester that many of you will already be aware of. You might have one, but, if you've never heard or it or didn't think it would be worth buying I wanted to say: think about picking one up.

It will do transistors, zeners, LEDs, rectifiers, switching diodes, caps, resistors, and inductors to reasonable accuracy. This particular version has a nice case and a built-in lithium battery. It also does IR remote testing and for some, decoding. It's quite a handy little box for the bench. I find it great for sorting the aftermath of a project and for confirming pinouts and component types.

The link is a cheap option: https://www.amazon.com/Pocketable-Colorful-Multi-function-Transistor-Capacitor/dp/B07HNTW3MP/ though not the vendor i purchased from who has raised the price to be out of line. Take a look, I think you'll find it useful.

 

Will it do a Vcesat test at a few mA ? Or Rdson for MOSFET ?


Regards, Dana.

 

They just keep getting better! 2 of the earlier models. The monochrome model is a tad larger and not as good on the extremely low-value capacitors. The second model is a bit different design and has a potentiometer to null on low capacitance and measures less than 10 pF. 2nd also a bit smaller and at a tilted angle sitting flat on the desk and somewhat color. It's handle was too short and I lengthened it with a bit of shrink tubing to extend out of the case. I'm not only having a hard time seeing these days, but also somewhat colorblind so I use it to sort resistors when tearing down breadboards. Third one is a chip tester. Basically a go-no go tester and maybe give an ID. Not really cheap and for only a limited number of chips. Good for 54/7400 series and some opamps and others.

 

They are very handy. I have one of the first shown in your post SamR. Well worth while getting!

 

Somewhat of a necropost follow-up. Bought the tester that @Yaakov posted about after he posted and just recently found that it reports very erroneous Hfe. In fact almost double the actual DC Beta. Anyone else??? My older models of the same basic tester are very close to the actual Beta calculated from Ic/Ib measurements.

 

Somewhat of a necropost follow-up. Bought the tester that @Yaakov posted about after he posted and just recently found that it reports very erroneous Hfe. In fact almost double the actual DC Beta. Anyone else??? My older models of the same basic tester are very close to the actual Beta calculated from Ic/Ib measurements.

When I get a chance, I will test this, Sam.

 

It is dead-on ~accurate on everything else. Even the transistor Vbe is spot-on. Without any documentation... Who knows... May be a programming glitch or mine is just off.

 

It is dead-on ~accurate on everything else. Even the transistor Vbe is spot-on. Without any documentation... Who knows... May be a programming glitch or mine is just off.

A quick check on four different transistors shows (according to datasheets, I don’t have another meter handy) slightly high readings. I have another meter I will have to dig up to compare, but it does seems high(ish) at least.

 

That was my impression from looking at datasheet specs. Once I actually put a ckt together and analyzed it I was surprised. So I drug out all 3 of mine. New one was Hfe 431 for 2n2222 (OK (IC = 10 mAdc, VCE = 10 Vdc, f = 1.0 kHz) hfe 300 375 so maybe possible but this is hfe), previous model 289, older model 286. Measured Ib 27uA, Ic 7.62mA for ßdc of 282 actual. It's more than a "little" high. Or at least mine is.

Edit: Argghhh brain fog again. It's hFE on the meter NOT Hfe... Need to check the AC signal Ic and Ib...

 

Sam the device looks useful for matching transistors. hfe is mildly useful as it changes quite a bit due to thermal properties. Been too busy to get one of these and test them. Last we discussed they have SMD pads which I would need to test mine. I would love something to quickly differentiate N and P channel mosfets. The tiny packages make them hard to keep separated at times. How quick is the capacitance reading?

 

Much much quicker than my bench meter although I haven't tested it on picos. I like the new one as it is much smaller than the older ones encased in the plexiglass boxes. It did die on me a while back and after a few days, I took a screwdriver to it. There is a connector between the battery which is glued to the back shell and the PCB to disconnect to fully open it. Didn't see anything suspicious and when I buttoned it back up it was working again so possibly just the battery connector loose. It does seem to hold it's charge well as I have only charged it once since I got it and that was when it died and thought maybe the battery was down. Very useful tool that I use more often than a DMM.

 

Some of the simpler charging circuits have a latching circuit for protection that requires a reset to power up again from battery after charging.

 

I have 1, it's the only working thing I have to test BJT gain. I'd like to know more how they actually work and what current they test beta with.

I should test that, and also compare it's ESR test to my LCR meter.

Overall I rarely use it, but it's nice to have, esp. for BJT and mosfets, for only $10-20

 

this was originally designed by Markus Frejec and further refined By others. The transistors are checked at 7mA. Here are some of the documentation.

https://www.mikrocontroller.net/articles/AVR-Transistortester
https://www.mikrocontroller.net/articles/AVR_Transistortester
http://bit.ly/2mnlQ2C

 

@Wolframore Last we discussed they have SMD pads The older models do but not this one. One of the older models has the pad but the plexiglass case covers it making it unreachable. Since I am usually putting together a test ckt on a breadboard and taking a quick DMM reading to check Meas Vs Calc, temp usually doesn't come into play and when it does yes the DMM meas will drift. Then I try and grab the quickest Cold Power-On meas. Yes, it works identifying FETs.

Thx for the background, I figured the chinese stole it from somewhere.

It is very useful for quickly finding which is which on the leads, EBC or CBE. Testing with an Ohm or continuity/diode meter is simple as the BJT transistor is simply 2 diodes back to back and opposing. Connect DMM lead to middle leg and test the outside legs. Polarity will tell whether NPN of PNP and you should have continuity between the middle leg and each outside leg.

 

You can't steal open source... too many folks do a lot of work then share it for the recognition without benefiting personally from their work. Many of us are just poor businessmen, we like the challenge but don't know the first thing about selling or pricing. One of my first projects for a client, I spent 2 months developing and I sold for $5 per unit while it cost me $3 to make. He sold them for $15. He still orders about 100/month... I'm not changing the pricing on him mid stream but will rethink pricing in the future. Then when he asked me to develop something that would take 6 months or longer and demanded a $12 price I declined.

That's how I test in circuit when I suspect a bad transistor... but when I have my SOT23 transistors, my vision is getting worse and hard to tell which ones I have. Mosfets are not as easy to test. I really have to squint and concentrate to tell the A6 vs A7 markings on my N and P mosfets I use. Now adding more transistors to my inventory will make things worse. An easy checker is always good. The other day my son mixed up my 1206 10u and 47u ceramic caps.... ugh I made him test and sort them. I suppose a SMT break out would be a good project.