328p/328 transistor tester

The source project address is provided here for reference:

EasyEDA project address: https://oshwlab.com/wagiminator/y-atmega-transistortester-smd

Original project address in Germany: https://www.mikrocontroller.net/articles/AVR_Transistortester

The main function:

ATmega328p Transitor Tester is a pocket version of the famous component tester developed by Markus Frejek and Karl-Heinz Kübbeler, with automatic detection of NPN and PNP bipolar transistors, N-channel MOSFETs, JFETs, diodes, dual diodes, N and P-IGBTs, Thyristors, Triacs, Inductors, Resistors and Capacitors.

Resistance measurement range 0.1 ohm - 50M ohm

Capacitance measurement range 35pf-100mf

Inductance measurement range 0.01mh——20h

The above is a translation.

For communication and communication, you can join the group: 215204131

In fact, as long as the calibration is done well, the error will be very small. My calibration is more casual, so the error is slightly larger.

Modify the description:

  1. Re-modify the PCB and schematic diagram, modify the layout, and add DIP14 package IC locking seats for patch test pads and connector testing

  2. The voltage reference source is modified to TL431, which can be replaced with the same pin.

  3. Modify the power supply interface to TYPEC interface for easy use and portability.

  4. The buttons are set to be side-mounted for ease of use. save space.

Demo:

Demo video: Simple transistor tester_bilibili_bilibili

1. SMD PMOS test  

2. SMD diode test

3. Electrolytic capacitor 1000uF test

4.1.5 ohm chip resistance test

Board display:

The materials used are only resistors, capacitors and voltage reference sources, crystal oscillators, microcontrollers, and buttons. The cost is less than 30 yuan. The microcontroller can be purchased from Lichuang overseas, and the cost can be as low as 20 yuan.

Production notes:

1. Be sure to write the fuse bit when burning the program, because the crystal oscillator was 8MHZ when the original author made it, so the fuse bit must be burned, otherwise the measurement will be abnormal. The fuse bit provided by EsayEDA version is

-U lfuse:w:0xff:m -U hfuse:w:0xdb:m -U efuse:w:0xfd:m

Low bit FF, high bit DB, extended bit FD. Other versions provide  low bit F7, high bit D9, and extended FC. The actual measurement can be used and no specific difference has been found. Select as appropriate, the EasyEDA version fuse bit currently used by the author.

2. Please note when using PROGISP to download, because the EEPROM is only 512 bytes when selecting the 328p chip but the actual 328pEEPROM size is 1k, so the display is incomplete. You can choose atmega329 for burning. Warning! ! ! Please pre-program the fuse bit and then set it to 329 programming program and EEPROM. Cancel the programming fuse bit operation during burning. Otherwise, if you perform this step incorrectly, the chip will be locked and there will be no solution. My attempt to unlock the crystal oscillator failed.

3.Attention !​ ! ! ! The calibration process is very important. You must choose a stable capacitor and a pure copper short-circuit pin, otherwise the measurement error will be large.

4. Please download the program first and then solder the DIP socket. The DIP socket will block the programming port.

5. The copper pillars used for installation are M2 8-10MM.

6. You can use CH341 to download the program but I have not tested it. For details, please refer to the CH341A-nextProgrammer multi-voltage dual-mode programmer-EDA open source hardware platform (oshwhub.com) and the burning software provided by this project.

7. Burning calibration operation View this project M328P transistor tester - Lichuang EDA open source hardware platform (oshwhub.com).

8. Please see the attachment for firmware. There are two types of attachments. One is the original version provided by EasyEDA Project and has not encountered problems yet. However, it has no menu settings and can only be tested. It is relatively simple. The second version has a menu function, but the actual test capacitance value has always been The reason for only half of the actual value is unknown. (It is speculated that this problem is due to the difference between 328P and 328 chips. I am currently using 328.) Anyone who knows the reason can comment and exchange.