| The LDR has a resistance
of about 1-10 M in the dark and about 100R in bright light.
It has a slow response to a change in light level. It is often used as a flame detector in furnace control systems. |
| Below is a simple light meter. |
| Here is a light operated
circuit.
If a dark operated circuit is required then reverse the positions of the LDR and variable resistor. |
Copyright Graham Knott 2004