Key relationship
Forward display≈Vf if test compliance≥Vf; reverse connection gives OL in this ideal test.
Physics · Practical apparatus
Diode and LED meter check
Use both lead orientations and compare silicon with an LED. A valid forward drop and reverse open indication are expected. An insufficient-compliance meter can show OL even for a working LED.
Open the interactive experiment →Diode and LED meter check
இரு முனைத் திசைகளிலும் சோதிக்கவும். LEDக்கு போதிய சோதனை மின்னழுத்தம் இல்லாவிட்டால் நல்ல கூறும் OL காட்டலாம்.
Key notes, relationships and model limits
Practical tip
Use both lead orientations and compare silicon with an LED. A valid forward drop and reverse open indication are expected. An insufficient-compliance meter can show OL even for a working LED.
Common trap
OL alone does not prove a device is faulty without checking orientation and compliance.
Model limits
Approximate fixed drops0.7 V silicon and2 V visible LED. Meter compliance may prevent a good LED from conducting; no component damage or breakdown model.
What you will learn
Interpret meter polarity and compliance in component checks.
Try the experiment
Try both scenarios, change one control, and predict the result before checking the graph and readouts.
Think of it this way
Change one input while keeping the others fixed, as you would in a controlled experiment.
Worked example
A3 V compliance meter reads0.7 V silicon or2 V LED in forward orientation.
Why this matters
The model connects diode and led meter check with an observable reading. Check the equation and assumptions before applying it.
Before you start
SI units · algebra · graph reading
Check your understanding
An LED needing2 V tested with1 V compliance gives?
- A guaranteed2 V reading
- OL in this model
- A negative resistance
Read the explanation
The meter cannot sustain the required forward drop.
Course connection: Virtual apparatus preparation. Check exact board/exam membership in the syllabus sources. Physical practical work remains necessary.