A bit unrelated, I wanted to ask if you'd ever managed to solve the problem with LC add-on where it was counting too many pulses.
...A problem with a thread as huge as this is that even when you know what you're looking for, it's not always easy to find. It would be nice to have either the first post or a separate page (or web site?) that links to the current important stuff: Where the current repository is, where the most updated documentation is, where the different modifications are described (like how to wire up a display for hardware SPI for example).
A bit unrelated, I wanted to ask if you'd ever managed to solve the problem with LC add-on where it was counting too many pulses.
The m-firmware expects the base frequency of the LC meter hardware option to be within a specific range. Do you mean this?
I know that many are unhappy with the tester that contains the APT32F172K8T6 (TC1 in my case).
But if you don't know anything about ATmega and firmware etc., it's not that bad for ~$10 including battery and case.
Despite the small battery, it has a really good endurance.
Once the problem with KAA range is solved (2K2 resistor) there is no reason to throw it away. Imo it's worth the money.
None of this is what I was asking. Looking to build, not buy. Need info.
I have several ATmega644 and ATmega1284 MCU chips in 40-pin DIP packages.
None of this is what I was asking. Looking to build, not buy. Need info.I am starting construction on a DIY Transistor Tester myself:
I have several ATmega644 and ATmega1284 MCU chips in 40-pin DIP packages. Actually the mega644 is big enough in terms of flash size. Enabling all available features in the OSHW Transistor Tester software does require an MCU with more than 32k of flash.
I intend to use a larger color LCD display than what comes in the ready-made Chinese units.
I plan to build the first unit on a “perma-proto” style board.
My version will have a high-quality rotary encoder for user input.
Yes. I remember it counting too many pulses at one end of the range, probably above 500nF (but, of course, now I can't find where I saw that being stated ).
It makes sense to build on this existing project. I have yet to find the original post in this thread about it.
https://github.com/madires/Transistortester-Warehouse/blob/master/Hardware/DevKit-644.kicad.tgz
I also have one of these LCR-style units with the APT32F172K8T6. My unit is reasonably accurate when testing R, C, L, or zener diodes.
However, I have noticed that it sometimes totally fails to correctly identify transistors by type. On a related topic it tends to display wildly inaccurate hfe values for some transistors which test consistently within the expected range by several other transistor testers which I have on hand.
Aldo22, Check these items from the list, if there are any in your household?
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg4610314/#msg4610314
10 fF - 33 nF
Aldo22 Check these items from the list, if there are any in your household?
3.Some BJT transistors (for example,2N5089,MPSA12,MPSA13, etc.) are defined as thyristors or resistors.
4.Some JFET transistors (e.g. J112,J113,2N5457, etc.) are not defined at all or are defined as BJT.
That's... a disappointingly short range. What's involved in the cleaning up of the signal? (I thought it came as a simple square wave at the output of the comparator.)
I like DIP because of the ease of swapping out the chip. What would be the advantage of an ATmega324 over ATmega328 to pay a premium for a tester based on it?ATMega324 has more I/O ports than ATMega328 DIP. Therefore, you simply have more chanses and options for connecting peripheral sources for the tester. I don’t see any more advantages.
Aldo22, Check these items from the list, if there are any in your household?
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg4610314/#msg4610314
Could it be that the APT32F172K8T6 version has a problem with lower hFE values (~<50) on BJT transistors?
It also identifies some of my fishy A42 as resistors (4 of 10). The same could be the case with your MPSA12 and MPSA13.
When I look at my Transistor Tester results I observe widely differing collector (or emitter) currents reported by the Transistor Testers
I only have a TC1 with the APT32F172K8T6 and a Fnirsi DSO-TC2.
The DSO-TC2 reports a range of Ic from ~2.5mA (mostly for NPN) to ~5.5mA (mostly for PNP) afaics, while the TC1 always shows ~6 mA (see my list above).
If you have a look a these curves, this might explain the big difference in some cases, e.g. for MPSA 42.
https://www.biophysicslab.com/2021/04/27/testing_transistor_hfe/
In most cases, however, 6mA seems to be a reasonable (average) value. EDIT: Not quite true. The DSO-TC2 sometimes reports Ie. A42, C1815
I wonder if FNIRSI makes these APT32F172K8T6 TC1 units?
I doubt it - I suspect the actual manufacturer "borrowed" the FNIRSI name to try to make their product look more legitimate.
Note: Pressing "Start" button 4 times in quick succession does cause my TC1 to display: FNIRSI-TC1 BOOTLOADER.