Potentiometers Research Paper Example

Our chosen vendor for the study of potentiometer is Arduino. The two potentiometers chosen for

our study are CA6 (Carbon Potentiometers) and CE9 (Cermet Potentiometers).

ELECTRICAL SPECIFICATIONS

Carbon Potentiometers (CA6)- Carbon potentiometers are electronic devices classified as variable resistor. It is used as voltage divider to get variable voltages. Carbon potentiometers can be classified into logarithmic and linear type. Depending on mode of operation. Specifications of CA6 Carbon potentiometer are as follows:

Range of Resistance 100ohm-5Mega Ohm

Max Power dissipation 0.15W (50 degree Celsius)
Max Voltage 200V (DC)
Operating Temperature -25 to +70 (Degree Celsius)
Cermet Potentiometers (CE9)- Ceramic materials are used in these potentiometers giving them a greater ability to absorb and dissipate heat. I.e. higher wattage rating. Cermet resistive elements have greater temperature operating range as compared to other substrates. Specifications of CE9 cermet potentiometers are as follows:

Range of Resistance 100ohm-5Mega Ohm

Max Power dissipation 0.5W (70 degree Celsius)
Max Voltage 200V (DC)
Operating Temperature -40 to +125 (Degree Celsius)

APPLICATIONS

Carbon Potentiometers (CA6)
Electronic Appliances, small household appliances.
Measurement and test equipments, timers and position control.
Cermet Potentiometers (CE9)
Small and high wattage household appliances.
Dimmers, Climate control and lighting sensors.
Heating and air-conditioning equipments including thermostats.
LINEAR VARIABLE DIFFERENTIAL TRANSFORMERS (LVDTs)
In our study of LVDTs we have studied the products of Measurement Specialities Inc. We have chosen Position Sensor ATA-2001 and Actuator Dual Channel LVDT.

Basic Operation of LVDT

In operation, the primary winding of LVDT is energised by AC of suitable amplitude and frequency, known as the primary excitation. The LVDT's electrical output signal is the differential AC voltage between the two secondary windings, which varies with the axial position of the core within the LVDT coil. Usually this AC output voltage is converted by suitable electronic circuitry to high level DC voltage or current that is more convenient to use. A comprehensive diagrams of LVDT is shown below. First diagram shows LVDT arrangement while second shows its application in a circuit.

PERFORMANCE SPECIFICATIONS

ATA-2001
Input Impedance 100 K Ohm
Transducer Excitation Voltage 0.5-3.5 VRMS

Transducer Excitation Current 45mA RMS (Max)

Transducer Excitation Frequency 2.5,5 or 10 KHz
Actuator LVDT
Maximum Loop Current 4-20mA
APPLICATIONS

ATA-2001 is used in Power-Generator Turbines, Precision metrology lab and position feedback.

Actuator LVDT is used majorly in military aircrafts and commercial aircrafts.
Important points about LVDTs and Potentiometers
Potentiometer is a device which measures voltage balance in the circuit. Basic circuit diagram of potentiometer is shown below. In its very basic form potentiometer is used for comparing emf of two cells and for calibrating ammeter, voltmeter and watt-meter.
Potentiometers can be classified on the basis of input (Adjustable Potentiometers), on the basis of relationship between input and output ( Linear Potentiometers) and on the basis of mechanical considerations ( Rotary variable resistors).

Some Popular vendors of Potentiometers are 4 Star Electronics, A2Z Electronics, AB & B Electronic supply.

LVDTs are electrical transformers which are used for measuring displacement.
LVDTs usually have three solenoid coils in which two outer coils are secondary and central coil acts as primary.
Core of LVDT is a ferromagnet.
7. Some modern applications of LVDTs are :

Measuring the right stroke for hydraulic applications.

Position measurement for steam control valves.
Petroleum Extraction: LVDTs are used for position control of downhole drilling equipment such as bore scopes that measures the inner diameter of drilled hole.