DROKTransistor Tester LCR Meter, Mosfet Transistor Capacitor Tester, Mega328 NPN PNP Transistor Diode Resistor Inductor Capacitance MOS SCR ESR Meter Automatic Checker Detector

One of my best purchases. It’s way more accurate than my DMM that has a built in tester. It will tell you what kind of component it is which is nice. Very useful for guitar pedals builders.

The Drok tester is similar to many units, but is better built than most. The product includes a zero insertion force socket which may be plugged into the header socket holes protruding from the front of the unit. The fit of the ZIF could be firmer, and it probably would have been just as well to mount the ZIF to the circuit board and not bother with headers.The operation is pretty straight forward and the unit had no trouble identifying various types of thyristors, junction transistors, MOSFETs and diodes I tried. The only device which tripped up detection was a 50 Amp Schotty diode, which showed as “no component.” To be fair, that diode also eluded an expensive tester. I know the diode is good because it behaves properly under load.I believe this tester is a handy addition to have on the work bench as long as you keep your expectations realistic about what it can do.

I rated this item three stars as I found that it is handy and works pretty nice. I’ve tested several items thus far and found that it is accurate and easy to use. Three cons on this device worth knowing. (1) It eats up batteries fast, and these 9v batteries ain’t cheap. (2) The fast insert device is nice, and pretty much necessary, but falls out easily. Mine has become a floor dweller on more than one occasion, because it will not stay inserted in the device. (3) Price - I found the same device on TEMU.com for $12.00! This is a Chinese company, and it will take two weeks to get the item. But all these inexpensive test fixtures are coming from China. And for $12.00 I can wait the two weeks.

I spend a good amount of time troubleshooting electronic faults at work, replacing faulty components. In many cases, I am working with circuit boards that I don't have the ability to power on the circuit using a DC power supply or batteries, for regular troubleshooting by measuring voltages with a DMM and a oscilloscope.This device is handy, it's always with me.For example, some LEDs can be tested using a DMM such as Fluke, set to the diode test measurement, depending on the power requirements for a particular LED and its color and illumination characteristics. On some LEDs one can see the diode light up briefly using a Fluke (or other DMM). Some LED's however will not illuminate using just a diode tester on a DMM. When testing LEDs, I reach for this device before a DMM, it reliably illuminates and LED with briefly or a rapid series of pulses, including Cree LEDs.As another reviewer has mentioned, not all circuit-testing is done on live circuits simply because the ability to energize the circuit may not be feasible or possible. This device has saved me a lot of time where a circuit arrangement that I test results in a complete oddball of a test result, such as reporting a double diode instead of a bijunction transistor, or other circuit boards do not result in the same repeatable test result for faulty boards, while the board is not energized.I could not do my work without a multimeter available as my most important tool, I simply wouldn't bother. At the same time, this device reports results that are arrived at by intuition and practice using just a DMM.One other valuable function of this device is that I can take a number of transistors and get a consistent reading for range of performance so that I can match a number of transistors in cases there they must perform almost equally well. Using this device is far simpler than creating a test fixture to test transistors so they can be matched. I do this even with resistors too, 1% tolerance sounds nice but is not always the case--I use the ohmmeter function on my DMM for that, it's simple. For testing transistors or diodes, this device makes segregating similar performers together, much simpler.I haven't even needed to change the 9V battery in almost two-years of use.

Works every bit as well as considerably more expensive models. I mostly use it for transistors, but it works for many other semiconductor types, as well. Measured beta is consistent with more expensive models. Battery lasts forever.

I acquired this after sending back another cheaper solution...twice. This one measures great so far - resistors, capacitors, diodes and transistors. Like other comments, the extra socket is a bit of an afterthought that tries to pop out when you push the lever down. For anything with two leads I've been using some jumpers that have mini-hooks on one end. One product suggestion: if they have anything to do with it, put the logo on the device label and put the website address in the manual. The startup delay is annoying and I don't really want to see it every time I power on.