DT-100, Transistor-Diode Tester, In-Circuit Testing, Polarity Indicators

The Elenco DT-100 Transistor-Diode Tester is a versatile tool designed for both hobbyists and professionals to assess the functionality of various semiconductor components. It allows for in-circuit testing of transistors and diodes, minimizing the need for component removal and thereby streamlining the troubleshooting process. The tester can identify NPN and PNP transistors, measure relative beta values, and determine the polarity of diodes, including LEDs and zener diodes. Its dynamic testing approach ensures accurate and reliable results, making it an essential addition to any electronics toolkit. ​

Key Features:

• Diode Testing: Checks all types of diodes, including germanium, silicon, power, LEDs, and zener diodes. Indicates cathode or anode leads and operates in-circuit with resistors as low as 5 kΩ. ​
• Transistor Testing: Evaluates all types of transistors—germanium, silicon, power, RF, audio, switching, and FETs. Identifies NPN and PNP types, measures relative beta, and can test transistors in-circuit with base or collector resistors as low as 100 Ω. ​
• In-Circuit Testing: Capable of testing transistors and diodes without removing them from circuits, provided certain resistance conditions are met. ​
• Polarity Indicators: Features LED indicators to show polarity for both transistors and diodes, aiding in quick identification. ​
• Dynamic Testing: Utilizes a dynamic testing method to provide accurate assessments of components' operational status. ​
• Battery-Powered: Operates on a standard 9V battery, ensuring portability and ease of use in various environments. ​

Additional Specifications:

• Compatibility: Transistors: NPN, PNP, germanium, silicon, RF, power, switching, FETs Diodes: Silicon, germanium, power, LEDs, zener In-Circuit Testing: Yes, for resistors ≥100 Ω (transistors) or ≥5 kΩ (diodes)
• Modes: Diode Test Mode: Indicates polarity (cathode/anode), forward bias Transistor Test Mode: Identifies type (NPN/PNP), checks junctions, gives relative β (gain) Dynamic Testing Method for operational status
• Accuracy: Qualitative / functional tester (no numeric accuracy rating) Provides polarity and go/no-go functionality, not quantitative values
• Range: Not specified in voltage/current terms — tests low-voltage characteristics of semiconductors In-circuit limits: ≥100 Ω (transistors), ≥5 kΩ (diodes)
• Display: LED Indicators (No numeric LCD or graphical display) Shows polarity and junction behavior via LED illumination