Engineering & Technology
WWW.CLARVIS.CO.UK
WWW.CLARVIS.CO.UK
A the name suggests, an LDR is a special type of resistor whose resistance changes dependent on the amount of light that shines on it.
When it is dark it has a high resistance and when it is light it has a lower resistance. The graph shows how an increasing light level affects its resistance.
The resistance of all resistors varies with temperature, but only by a very small amount. A thermistor is a type of resistor that is designed to have a large change in resistance relative to its temperature.
The resistance of NTC thermistors (negative themal constant) decreases with themperature.
The resistance of PTC thermistors (positive temperature co-efficient) increases with temperature.
