The ATmega328p Transistor Tester is a pocket-sized version of the famous component tester developed by Markus Frejek and Karl-Heinz Kübbeler featuring automatic detection of NPN and PNP bipolar transistors, N- and P-channel MOSFETs, JFETs, diodes, double diodes, N- and P-IGBTs, thyristors, triacs, inductors, resistors and capacitors.
Transistor Tester Characteristics with Atmega Mini SMD PCB
- One-key-operation
- Three test pins for universal use.
- Automated detection of NPN, PNP, N- and P-channel MOSFET, JFET, diodes und small thyristors, TRIAC.
- Automated detection of pin assignment, this means the device-under-test can be connected to the tester in any order.
- Measurement of hFE and base-emitter-voltage for bipolar junction transistors, also for Darlingtons.
- Automated detection of protection diodes in bipolar junction transistors and MOSFETs.
- Bipolar junction transistors are detected as a transistor with a parasitic transistor (NPNp = NPN + parasitic PNP).
- Up to two resistors will be measured with a resolution down to 0.1 Ohm. The measurement range is up to 50 MOhm (Megaohm). Resistors below 10 Ohm will be measured with the ESR approach and a resolution of 0.01 Ohm. Beware: resolution is not accuracy.
- Capacitors in the range 35pF (picofarad) to 100mF (millifarad) can be measured with a resolution down to 1 pF (0.01 pF for capacitors with lower capacity than 100 pF).
- Resistors and capacitors will be displayed with their respective symbol, pin number and value.
- Up to two diodes will also be displayed with their correctly aligned symbol, pin number and voltage drop.
- If it’s a single diode, the parasitic capacitance and reverse current will also be measured.
- Inductances of 0.01 mH to 20 H can be detected and measured.
- A measurement of ESR (Equivalent Series Resistance) of capacitors greater than 20 nF is built in. The resolution is 0.01 Ohm. For lower capacity values the accuracy of ESR result becomes worse.
- Vloss of capacitors greater 5 nF is examined. With this, it is possible to estimate its Q-factor.
Please be aware that the test inputs lack a protective circuit, which could potentially lead to inaccurate measurement results. Before connecting the capacitors to the tester, it is crucial to discharge them. Failure to do so may result in damage to the tester even before it is powered on. When attempting to test components that are mounted on a circuit, exercise caution and ensure that the device is disconnected from the power supply, with no remaining voltage.
Transistor tester scheme with Atmega mini PCB SMD
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Testing a Component
- Connect the Transistor Tester via the Micro-USB port to a 5V power supply.
- Plug the component to be tested into the socket row. Each pin of the component should have its unique socket number (1 to 3).
- Press the TEST button and wait for the result shown on the OLED display.
Characteristics
| Component | Measuring Range |
|---|---|
| Resistors | 100mOhm – 50MOhm |
| Capacitors | 35pF – 100mF |
| Inductors | 0.01mH – 20H |
| Z-Diodes | max 4.5V |
BOM for assembly of the Tester Transistor with Atmega
| Parts | Value | Description | Quantity |
| Capacitors | |||
| C1,C2 | 100n | SMD Capacitor 0603 | 2 |
| C3 | 1n | SMD Resistor 0603 | 1 |
| C4 | 47u | SMD Resistor 0603 | 1 |
| C5,C6 | 22p | SMD Resistor 0603 | 2 |
| ICSP-6 | ICSP | Pin Header Connector 2 × 3 Pins | 1 |
| Resistors | |||
| R1 | 10K | SMD Resistor 0603 | 1 |
| R2 | 1,5K | SMD Resistor 0603 | 1 |
| R3 | 27k (273) | SMD Resistor 0603 | 1 |
| R4,R6,R8 | 680R (681) 1% | SMD Resistor 0603 | 1 |
| R5,R7,R9 | 470k (474) 1% | SMD Resistor 0603 | 1 |
| R10 | 2k2 (222) | SMD Resistor 0603 | 1 |
| Semiconductors | |||
| U1 | ATMEGA328P-AU | AVR Microcontroller | 1 |
| U2 | U2 LM4040DYM3-2.5-TR | SOT-23 (SOT-23-3) Voltage Reference | 1 |
| LED1 | Led azul | Led 0603 | 1 |
| OLED | OLED | Display Oled 128×64 0,96 4 pin | 1 |
| Miscellaneous | |||
| Touch switch | TEST | SW-SMD_4PIN-L12.0-W12.0-H6.0 | 1 |
| Header | TESTPORT | Test connector, HDR-6×1/2.54 | 1 |
| USB | Power connector, USB | Micro-USB 2 Pins connector | 1 |
| X1 | 8 MHz | Crystal Quartz HC-49SMD | 1 |
Souce: https://oshwlab.com/wagiminator/y-atmega-transistortester-smd
License: CC-BY-SA 3.0
