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Custom and Semi-Custom Devices

Upon request, and where sufficient quantities are involved, PerkinElmer Optoelectronics will test standard parts to your unique set of specifications. The advantage of testing parts under actual operating conditions is predictable performance in the application.

PerkinElmer offers a broad line of standard photodiodes in a wide variety of packages and sensitivities. Nevertheless, some applications demand a totally custom device. Recognizing this real need, PerkinElmer’s engineering, research, and sales departments are geared for working with the customer from initial concept through design, prototype, and volume production.

Photoconductive Cell Typical Applications

Why Use Photocells?

Photocells can provide a very economic and technically superior solution for many applications where the presence or absence of light is sensed (digital operation) or where the intensity of light needs to be measured (analog operation). Their general characteristics and features can be summarized as follows:

• Lowest cost available and near-IR photo detector

• Available in low cost plastic encapsulated packages as well as hermetic packages (TO-46, TO-5, TO-8)

• Responsive to both very low light levels (moonlight) and to very high light levels (direct sunlight)

• Wide dynamic range: resistance changes of several orders of magnitude between light and no light

• Low noise distortion

• Maximum operating voltages of 50 to 400 volts are suitable for operation on 120/240 VAC

• Available in center tap dual cell configurations as well as specially selected resistance ranges for special applications

• Easy to use in DC or AC circuits - they are a light variable resistor and hence symmetrical with respect to AC waveforms

• Usable with almost any visible or near infrared light source such as LEDS; neon; fluorescent, incandescent bulbs, lasers; flame sources; sunlight; etc

• Available in a wide range of resistance values

Applications

Photoconductive cells are used in many different types of circuits and applications.

Analog Applications

• Camera Exposure Control

• Auto Slide Focus - dual cell

• Photocopy Machines - density of toner

• Colorimetric Test Equipment

• Densitometer

• Electronic Scales - dual cell

• Automatic Gain Control - modulated light source

• Automated Rear View Mirror

Digital Applications

• Automatic Headlight Dimmer

• Night Light Control

• Oil Burner Flame Out

• Street Light Control

• Absence / Presence (beam breaker)

• Position Sensor