Features

This infrared light source is a thermal emitter with an emissivity of ~80%. It is appropriate for use in laboratory or field instrumentation due to its long life and stable properties.

The coiled filament operates at ~800°C when powered with 4 watts for the IR-21 and 3.4 watts for the IR-22. The radiating element is a coiled resistance wire which has a high emissivity in the infrared spectral region. The coil is supported on a cylindrical substrate of alumina. Due to the reduced mass of this unit it can be pulsed at up to 1 hertz with a resultant temperature variation that can be detected though the depth of modulation is small. For better pulsed infrared light source operation please see the IR-40 and IR-50 sources. The unit does not require operation in a sealed atmosphere.

The header is available in two sizes. The larger, IR-21, has an 8.6 mm diameter base. The smaller, IR-22, has a 4 mm diameter base. The support pins, which are also the power leads, are hermetically sealed in glass.

The IR-20 Series is offered in two configurations: the IR-21 and IR-22 have the element mounted horizontally and the IR-21V and IR-22V which have the element mounted vertically.

Operating Specifications IR-21 and IR-21V

	Voltage: 5 Volts (AC or DC)
	Temperature: 800°C
	Current: 0.8 Amps
	Power: 4.0 Watts
	Active area: 1.5 mm x 3.5 mm
	Emissivity: 0.80
	Lifetime: 3+ years at 800°C, typical

Operating Specifications IR-22 and IR-22V

	Voltage: 4.5 Volts (AC or DC)
	Temperature: 800°C
	Current: 0.75 Amps
	Power: 3.4 Watts
	Active area: 1.5 mm x 3.5 mm
	Emissivity: 0.80
	Lifetime: 3+ years at 800°C, typical

Spectral Radiance

Spectral radiance output for a perfect black body of various temperatures. The IR-21, IR-21V, IR-22 and IR-22V produces approximately 80% of these figures in the 1µm to 22µm range.

Ordering Information

Accessories

The combination of the IR-21V and the MC-233 Elliptical reflector creates an output image as shown below. The majority of optical output is concentrated within an approx 3mm circle 12mm from reflector. Please note, the infrared output is just strong enough to char paper and that the shadow cast from the element support can be seen.

By using an IR-21V, an MC-233 elliptical reflector and a piece of fax paper, it is possible to monitor how quickly the IR-21V heats up. Full power is reached approximately 15 seconds from switch on, though the infrared output continues to increase as the reflector heats up. (Approx 2.5 second exposure at each point)

Useful Documents

Infrared Source Series 20 Data Sheet - pdf (82K)