Here I want to list the most important properties

Works with ATmega8, ATmega168 and ATmega328 processors.
Display of measurement results on a 2x16 character LCD.
Instead the 2x16 character LCD can also be used with a graphic display ST7565 Controller. A connection of an OLED display with SSD1306 controller is possible with SPI or I2C interface.
One-button operation with automatic switch-off.
The device has three universal Meßports (test pin).
Automatic detection of NPN, PNP, N- and P-channel MOSFET, JFET, diodes and small signal SCR and TRIAC.
Automatic recognition of the pin assignment of the components, the components can be connected either way.
Measurement of the current amplification factor and the base-emitter voltage for bipolar transistors, Darlington transistors also.
Automatic detection a protection diode for bipolar transistors and MOSFETs.
In bipolar transistors with protective diode a parasitic transistor is detected (npnp = + NPN parasitic PNP).
Up to two resistors are measured in a measurement with a resolution of up to 0.1 ohms, the range extends to over 50 megohms. Resistance values ​​less than 10 ohms will be displayed for the ATmega168 / 328 with the ESR measurement method with a resolution of 0.01 ohms.
A connected capacitor can be measured in the range 35pF to 100mF with a resolution of up to 1 pF.
Resistors and capacitors are represented by their symbols, surrounded by the terminal pin numbers found.
The resistor and capacitor values ​​are shown with up to four decimals in the correct dimension.
Up to two diodes are also displayed flußrichtungsrichtig with their symbolic representation, surrounded by the connector pin numbers and the additional indication of the forward voltage.
In addition the individual diode capacitance value and version 1.08k also the current in the reverse direction is measured.
For ATmega168 / 328, a calibration of the zero capacity, the zero resistance and other parameters in the self-test branch is possible.
For ATmega168 / 328 also inductances of about 0.01mH can be detected and measured to over 20H.
For ATmega168 / 328 an ESR measurement (Equivalent Series Resistance) is integrated for capacitors than 90 nF with a resolution of 0.01 ohms.
for ATmega168 / 328, the voltage loss VLOSS is examined after a charging pulse for about 5 nF capacitors. Thus, the quality of the capacitors can be estimated.
for ATmega328 other functions from a list are presented with a menu function, the (> 0.5 s) can be called with a long keypress, possible. A short key press shows the next function. An extended keypress launches the function displayed. Below is a list of previously installed extra functions:
Frequency measurement on the PD4 pin, but which is also used for the LCD connection. The pin is switched for measurement on input. The applied frequency is first counted for 1 second. If the frequency is below 25 kHz, and an average period is measured and used to calculate a frequency with a resolution of up to 0001 MHz.
Voltage measurement at PC3 pin when it is not used for the serial output. In ATmega328 32-pin (PLCC) but can also ADC6 or ADC7 pin be used. Since a 10: 1 divider is used at the input, voltages can be measured up to 50V. With an extension of the circuit (DC-DC Converter) Zener diodes can also be measured.
Frequency generation at TP2 port. PB2 through the connected at pin 680 ohm resistor, a signal having an adjustable from a list of frequency of 1 Hz to 2 MHz on port TP2 to be output. The TP1 port is connected to ground.
Pulse width modulation at a fixed frequency and adjustable pulse width TP2 on the port. The counter 1 is used for this function as 10-bit counter. The TP1 port is connected to ground. The pulse width can be increased by pressing the button briefly to 1% and prolonged keystroke by 10%.
With a separate capacity and ESR measurement can be measured to 50mF usually also in the circuit connected to TP1 and TP3 capacitors with a capacity of about 2μF. Here, however, should always be ensured that the capacitors have no remaining charge.