Spark image
Sensors

Light dependent resistor (LDR)
This is a resistor which has a resistance that changes with the amount of LIGHT that falls on It. In the DARK its resistance is LARGE (millions of ohms), in the LIGHT its resistance is SMALL (tens of ohms). Very little current will flow through it in the dark.


Thermistor
This is a type resistor which has a resistance that changes with TEMPERATURE. In the COLD its resistance is LARGE (thousands of ohms), in the HEAT its resistance is SMALL (tens of ohms). Very little current will flow through it when it is cold.

 
 
 
© Keith Gibbs 2009