VT33CT datasheet(13/76 Pages) PERKINELMER

13 / 76 page

Selecting a Photocell

Many low voltage situations involve very little power, so that the

photocell can be small in size, where voltages and/or currents are

higher, the photocell must be physically larger so that the

semiconductor film can dissipate the heat.

The following curve of power dissipation versus ambient temperature

describes the entire series of cells for operation in free air at room

ambient (25°C). Note that regardless the size, all photocells derate

linearly to zero at an ambient temperature of 75°C. The adequate heat

sinks can increase the dissipation by as much as four times the levels

shown in this graph.

Maximum Cell Voltage

At no time should the peak voltage of the cell exceed its maximum

voltage. the designer should determine the maximum operating or

peak voltage that the cell will experience in the circuit and choose an

appropriately rated cell. Typical voltage rates range from 100V to 300V.

What Type of Material is Best?

Each specific material type represents a trade off between several

characteristics. Selecting the best material is a process of determining

which characteristics are most important tin the application.

PerkinElmer’s standard photocells in this catalog are manufactured

using one of two different material types offered: type “Ø” or type “3”.

In general, material type “Ø” is used for applications such as

nightlights, automotive sensors. Material type “3” is primarily used in

camera, streetlight control, and flame detector applications.

VT33CT Datasheet(PDF) 13 Page - PerkinElmer Optoelectronics