Inexpensive Test Equipment
We owe it to our youngsters or their friends to provide encouragement and assistance in developing their interests into a viable career. So, with Issue #130 of the Z-100 LifeLine, I decided to introduce you to a source of inexpensive test equipment for individuals interested in electronics. For about $15-25.00, you can now buy test equipment of all kinds from Ebay and China that would make an excellent gift for some individual interested in a career in electronics. Most of these are in kit form; in some cases, really nothing more than a circuit, but in many cases with capabilities beyond imagination.
Here are several that I have found and the documents that I have created to support each of them. Feel free to check out their documentation before going to Ebay to purchase. I will be adding more as time permits. Just click on the links to read and/or print the documentation.
One word of caution. I’ve now constructed several of these kits and you must remember that these are simple kits with amazing capabilities built in. However, you also get what you pay for - that is, these are not designed with a lot of care to part tolerances and have no additional delicate corrective circuitry. So, not all of these will work as they should. Some of the kits I constructed came with a bad or incorrect part. So always test the parts that you can BEFORE installation. Some completed kits did not have the full frequency range specified. One Transistor Tester, in spite of all I did and checks that I made, just would not work.
Nevertheless, those that did work are utterly amazing in what they can do in such a small package. My recommendation: At prices this low, buy the equipment in pairs. Odds are that at least one will work. Also, you have spare parts, if you need them, which also helps in troubleshooting a bad unit. At these prices, it is best for a little insurance. Finally, while some units are available from sources within the States, in most cases, these units are ordered from China and will take up to six weeks to receive.
Now, let's check out those I've completed so far. Future projects include a few simple oscilloscopes.
Mega328 LCR-T4 Transistor Tester: Actually, if you go online, the description of this unit is: Mega328 LCR-T4 ESR Transistor Tester Diode Triode Capacitance SCR Inductance. The Mega328 Transistor Tester, model LCR-T4, comes as a fully assembled board, but without the wood block shown in the picture. The wood block just makes the unit more stable by giving it some weight. It is often sold with an acrylic case, or the case may be purchased separately. The Tester will automatically detect NPN, PNP, and Field Effect Transistors (FET), diodes (including dual diode, zener diode and light emitting diode), triodes, thyristors, triacs, and SCRs, with automatic identification of the transistor pinout. It also tests resistors (including adjustable potentiometers), capacitors, and inductors. Documentation is here: Mega328 Transistor Tester.
GM328 Transistor Tester & Frequency Generator: The GM328 Tester has most of the same capabilities as the earlier Mega328, but has several new capabilities. Most impressive - this tester includes frequency generation and a frequency counter. The GM328 Transistor Tester is sold as a kit and requires some experience in soldering skills as three of the parts are small surface mounted devices. The Tester will automatically detect NPN, PNP, and Field Effect Transistors (FET), diodes (including dual diode, zener diode and light emitting diode), triodes, thyristors, triacs, and SCRs, with automatic identification of the transistor pinout. The Tester detects power transistors with FET protection diodes built in. It also tests resistors (including adjustable potentiometers), capacitors, and inductors. This Tester can also generate a single square wave with 20 set frequencies from 1Hz to 2.0MHz, can measure frequencies from 1Hz to 2.9MHz with resolution to 0.001mHz, and can use an AC/DC power adapter (6.8-12Vdc, 30mA current).
Caution: This is the kit where I could not get one to work, so I ordered a third. I swapped most of the parts out, but it would take 90 seconds before turning ON, then go straight into the calibration test. Parts swapped to an operable unit, still worked. So, it is still a mystery to me why such a simple circuit acts so weird. Nevertheless, I still recommend purchasing one (or two) of these for its amazing capabilities at low cost. Documentation is here: GM328 Transistor Tester Assembly and GM328 Transistor Tester Manual.
DL4YHF2 Frequency Counter & Crystal Tester Manual: The DL4YHF Frequency Counter & Crystal Tester is sold as a kit and requires some experience in soldering skills. A soldering iron with a needle point tip would be very helpful here. The kit comes with NO instructions, but I found everything on the internet. I have assembled the kit, created a schematic, added the ability to check 4-pin crystal oscillators, and included everything in my manual. This is a five-digit frequency counter kit based on a PIC single chip 16F628 micro-controller, with a crystal oscillator measurement function, programmable frequency setting, and LED digital display. It is most commonly used to measure the oscillation frequency of a crystal. The Part/Model Number can be found as YS9283, B8O8, and many others, but it is actually a generic, unbranded circuit board based on a circuit developed by Wolfgang Buscher, DL4YHF. All the parts are through hole components, so the kit is easy, and simple to operate. Documentation is here: DL4YHF2 Frequency Counter & Crystal Tester Manual.
Note: The kit does NOT include the plastic piece, ZIF socket, BNC connector, or the crystal oscillators shown in the picture. For that matter, they are not actually needed. Instead of the ZIF socket, you could just as easily add a normal 14-pin IC socket - I show one in the documentation. I added the ability to test the 4-pin crystal oscillator, so I will call the modified device the DL4YHF2 Frequency Counter and Crystal Tester.
DS150 Oscilloscope: To be covered next time.