Test with a multimeter

LDR (photoresistor)

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Now: Resistor value in the light

✋ CircuVanta 6000 counts · auto range DCAUTO•)))HOLDFUSE− HOLD LIGHT OFFV⎓V~Ω•)))FmA⎓ mA400 mACOMVΩ Pin 1 1 Pin 2 2
Pin 1: Pin 1 (1) Pin 2: Pin 2 (2)

Red probe Not connectedBlack probe Not connected

Hold the probe and drag it to the tip of a leg. Tapping works too: first pick the probe, then the leg.

Set the range to Ω (resistance).

Measure step by step

An LDR is a sensor whose resistance drops as light increases; it has no direction. Measure first in dim room light, then with the top covered. In the dark the resistance rises a lot.

  1. 1Resistance in light
  2. 2Cover it: resistance in the dark