NA431 Battery Button Transistor Tester (LCR-T4)
The NA431, also known as the LCR-T4 graphical tester, is a versatile device for testing electronic components. It is designed to work with ATmega8, ATmega168, or ATmega328 microcontrollers and features a 2x16 character LCD display.
Key Features and Capabilities
- Power Management: Features one-click operation with automatic power-off. The shutdown current is a low 20 nA, supporting battery operation. The low-cost version does not require a crystal oscillator and supports automatic power off. Versions using ATmega168 or ATmega328 with 1.05k software utilize sleep mode to reduce power consumption when not in use.
- Component Detection: Automatically detects PNP and NPN bipolar transistors, N-channel and P-channel MOSFETs, JFETs, diodes, dual diodes, and thyristors. It also automatically detects the pin layout of these components.
- Transistor Testing: Measures the current amplification coefficient (hFE) and threshold voltage of the emission junction for bipolar transistors. Darlington transistors can be identified by their high threshold voltage and high current amplification coefficient. It also detects protective diodes for bipolar transistors and MOSFETs.
- MOSFET Testing: Measures the threshold voltage and gate capacitance value of MOSFETs.
- Resistor Measurement: Supports the measurement and symbol display of two resistors, showing up to four digits and units. The resistance symbol indicates the connected tester probe numbers (1-3) at both ends. This allows for potentiometer measurement. Note: If a potentiometer is adjusted to one end, the tester may not distinguish between the pins in the middle and at both ends. The resolution for resistance measurement is 0.1 ohms, with a maximum measurable value of 50M ohms.
- Capacitor Measurement: Detects and measures capacitor values, displaying the highest four digits and units. The measurable range is from 25pF (at 8 MHz clock, 50pF at 1 MHz clock) up to 100mF. The resolution can reach 1 pF (at 8 MHz clock). It can also measure the equivalent series resistance (ESR) for capacitors above 2uF, with a resolution of 0.01 ohms and two-digit display. This ESR measurement requires at least 16K flash memory on the ATmega microcontroller. Capacitors below 25pF are usually undetectable but can be measured if connected in parallel with a diode or a capacitor of at least 25pF, requiring subtraction of the parallel capacitance value.
- Diode Testing: Displays symbols in the correct direction for two diodes, along with the positive voltage drop. LED detection identifies diodes with a forward voltage drop higher than normal. Double light-emitting diodes are detected as double diodes. Zener diodes with a reverse breakdown voltage below 4.5V are detected and displayed as two diodes, identifiable by voltage. The symbols around the probe indicate the same diode type. The true anode can be identified by a threshold voltage near 700 mV. If more than 3 diode-type parts are detected, it displays a failure message. This occurs if a diode is connected to all three probes and at least one is a diode type. In such cases, connect only two probes and perform measurements sequentially. The capacitance value of a single diode can be measured in the opposite direction.
- Inductance Measurement: Resistance below 2100 ohms can be measured as inductance if the ATMEGA has at least 16K flash memory. The range can exceed 20H from 0:01mH, but accuracy may be limited. Results show a single component connection.
- Testing Time: Standard testing time is approximately two seconds. Capacitance and inductance measurements may take longer.
- Self-Check and Calibration: Features a built-in self-check function and optional 50Hz signal check for clock frequency accuracy. It also includes an optional device calibration port output for internal resistance and zero offset self-check. A 100nF to 20uF capacitor connected between pins 1 and 3 can compensate for offset voltage of the analog comparator, reducing measurement error for capacitors above 40uF.
- Advanced Component Detection: Thyristors and bidirectional thyristors can be detected if the test current exceeds the maintenance current. However, performance for some semiconductor thyristors and bidirectional thyristors may vary.
Technical Specifications Summary
- Microcontrollers Supported: ATmega8, ATmega168, ATmega328
- Display: 2x16 Character LCD
- Power Consumption: Shutdown current typically 20 nA
- Resistance Measurement Range: 0.1 ohm to 50M ohm
- Capacitance Measurement Range: 25pF to 100mF
- ESR Measurement Resolution: 0.01 ohm
- Capacitance Measurement Resolution: 1 pF (at 8 MHz clock)
- Zener Diode Detection: Up to 4.5V reverse breakdown voltage
