An electronics technician uses an ohmmeter to test an unmarked semiconductor diode. When the positive lead is placed on Terminal 1 and the negative lead on Terminal 2, the meter indicates a low resistance. When the meter leads are reversed, the meter indicates infinite resistance (an open circuit). Based on these test results, which of the following conclusions is correct?
- Terminal 1 is the anode, Terminal 2 is the cathode, and the diode is operational.Answer
- BTerminal 1 is the cathode, Terminal 2 is the anode, and the diode is operational.
- CThe diode is defective with an internal short circuit because it conducts current during testing.
- DThe diode is defective because a healthy component must maintain equal bidirectional current flow.
Answer
Terminal 1 is the anode, Terminal 2 is the cathode, and the diode is operational.
A properly functioning semiconductor diode conducts current when forward-biased (positive potential on the anode, negative potential on the cathode) and blocks current when reverse-biased (positive potential on the cathode, negative potential on the anode). Because the ohmmeter indicates low resistance when the positive lead connects to Terminal 1 and the negative lead connects to Terminal 2, Terminal 1 is the anode and Terminal 2 is the cathode. The infinite resistance displayed upon reversing the leads verifies that the PN junction is intact and the diode is operational.
Step-by-Step Solution
Key Concept
Diode terminal identification and continuity verification using front-to-back resistance measurements
Estimated Time:1m 0s