LDR

LDR1 (left) & LDR2 (right)

Light Dependent Resistor (LDR) or commonly known as CdS (Cadmium sulfide) cells is an electronic component that changes its resistance based on the light level. The are 2 LDRs used in the Minox 35. One is connected to the light meter (indicator) and the other is for timing the close shutter (exposure).

* Both LDR’s resistance rises in the dark till 40MΩ and then it turns off (digital multi-meter shows an open contact)

The reason that LDR1 has a slower response time is so that the light meter needle in the viewfinder will move gently in response to changes in light levels.