OMEGA 44203 Offers

For applications requiring thermistors with linear response to temperature change, OMEGA offers linear components. These unique devices consist of a thermistor composite for temperature sensing and an external resistor composite for linearizing.

Industrial linear thermistor composite and probe. The linearized thermistor network provides a near-linear resistance output over its operating range for direct temperature measurement.

Thermistor composites 44018 and 44019 each contain two thermistors packaged in a single sensor. Thermistor composite 44020 contains three thermistors packaged in a single sensor.

Resistor composites for use with 44018 and 44019 thermistor composites consist of two metal film resistors of the size shown. Resistor composites for use with the 44020 thermistor composite consist of three of the same type metal film resistors.

Linear components are manufactured with different values for different temperatures ranges. When they are connected in networks, they produce a varying voltage or resistance which is linear with temperature.

If R is a thermistor, and Eout is plotted versus temperature, the total curve will be essentially non-linear and of a general "S" shape, with linear or nearly linear portions near the ends and in the center.

If R is modified by the addition of other thermistors and resistors, linearity of the center section of the curve, where sensitivity is greatest, can be extended to cover a wide range of temperatures.

Sensitivity is 400 times greater than an IC thermocouple. Thermistor values as high as 30 mV/°C are common. In addition, output voltage can be applied to a recorder or digital voltmeter to produce a precise, sensitive, direct reading thermometer.

The 44018 thermistor composite is used in four of the linear components. The part that changes in each component is the resistor composite, which determines the temperature range. Therefore, the 44018 thermistor composite can be used over the entire -22 to 212°F (-30 to 100°C) temperature range by simply changing resistor composites.

It is not mandatory that OMEGA(R) resistor composites be used with the 44018 thermistor composite. Any 0.1% resistors of the proper values and with a temperature coefficient of 30 PPM or less may be substituted.

In other situations, it is frequently desirable to have thermistor composite temperature sensors at more than one location. When this is required, it is not necessary to have a separate resistor composite for each thermistor composite. It is possible to multiplex any number of thermistor composites through a single resistor composite for greater design flexibility.

Features

• Linear thermistor network
• Industrial probe construction
• Near-linear resistance output
• Composite thermistor and probe assembly

Applications

• Industrial temperature measurement
• Producing a precise, direct-reading thermometer by applying output voltage to a recorder or digital voltmeter
• Process temperature monitoring
• Building a direct-reading differential thermometer from a 4-digit digital voltmeter
• OEM temperature sensing
• Multiplexing multiple thermistor composites to a single signal-conditioning circuit
• Laboratory temperature measurement
• Remote temperature sensing located up to distance D from the signal conditioning circuit using a 2-wire system
• Linear temperature readout
• Linear temperature monitoring across the -22 to 212°F (-30 to 100°C) range by changing resistor composites