Usage of Transducers Used in Potential Dividers

When we speak into a microphone → sound waves are converted into electrical signals through the use of an electronic device known as transducer

Transducers convert charges in physical conditions → such as pressure, temp or light, into electrical signals so that these physical conditions can be measured

Another eg; of transducer → is magnetic pickup that is commonly used in electric guitars.

• they allow sound of the instrument to be heard.
• done by converting the sound into an electrical signal that is then transferred into a sound amplifier.

Wide range of transducers:

• Thermistors
• Light dependant resistors (LDRs)
• Photovoltaic cells
• Piezoelectric sensors

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Thermistors

• type of semiconductor

resistance of thermistor varies with temperature → and thus thermistors are also thermally sensitive resistors. A negative temperature coefficient (NTC thermistor → is one where its resistance decreases with temperature.

Thermistors → very accurate + cost effective sensors for measuring temp.

• one of the resistors is replaced by NTC thermistor if temp. increases → resistance of NTC thermistor $R_{TH}$ would decrease by disproportionally higher amt. → causes output voltage $V_{out}$ to increase. → increase in $V_{out}$ can be measured to determine the increase in temp.

1. output voltage is given by: $V_{out}=\frac{R}{R+R_{TH}}\times V_{\mathcal{E}}$ where R = resistance of the fixed resistor ($\text{ohm}$) $R_{TH}$ = resistance of the thermistor ($\text{ohm}$) $V_{\mathcal{E}}$ = voltage supplied by electrical source (V)

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Light Dependant Resistor (LDR)

• responds to light same way as NTC thermistor responds to temp.
• as amt of light shining on LDR increases, the resistance of LDR decreases.
• like thermistors → LDR also made from semiconductors

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