Notes

Slide Show

Outline

1	Resistive Transducers Sensors Used in Electronics
2	Key Ideas Resistive transducers are passive devices. They do not generate an electric current. Their resistance changes in response to a change in the environment. They are usually found in a potential divider circuit. When the resistance changes, the voltage balance changes. The processor detects the change.
3	Light Dependent Resistor
4	LDR in Circuits Here we see the LDR in a potential divider circuit. In this case Vout will go up as the light level goes up. The next slide shows the LDR in a circuit.
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6	Thermistor
7	Thermistor in a Circuit The thermistor has a resistance that changes as the temperature changes. In a negative coefficient component, the resistance goes down as the temperature goes up. In a positive coefficient thermistor, the resistance goes up with temperature.
8	Thermistors The thermistor does not generate electricity with increased temperature. A thermocouple does. Don’t confuse the two!
9	Potential Divider A simple but very useful circuit. Vout = Vin ×__R2__ R1 + R2 This applies when there is no load. If there is a load, treat it as a series and parallel resistor combination.