Selection of infrared components and calculation

In summary, the conversation is about seeking advice on selecting and calculating an infrared sensor for a simple PLC control system. The user wants a detection range of 30-45 degrees and 1 metre in length, and is considering using a phototransistor for the receiver. They are unsure about how to amplify the signal to 24V and if the phototransistor works the same way as a regular transistor. They also ask for advice on using an op-amp for amplification. An expert suggests using a common collector or common emitter photo transistor circuit and provides a link for more information.
  • #1
StealthRay
51
0
Hello,

Can any experts give me some advice on the selection and calculation of infrared in control.

I want to do a simple sensor control by PLC which utilize the infrared.When the receiver detects the infrared from the transmitter, the signal will trigger the PLC for some form of control.

At this point, photo sensitivity, wavelength, noise is not of my concern.However,I want the range of detection to be about 30-45 degree and at the length of about 1 metre.

I thought of using phototransistor because i saw some receiver circuits using it. My problem is how do I amplify the signal to 24v so that the PLC can recognize it. Is phototransistor works the same way as the transistor?Is the calculation similar in obtaining the Ic, Ib, and Vce?

Can the phototransistor works like the transistor and amplify the output voltage Vc to 24V?
If not should I use another transistor to do that?Or should I use an op-amp to do that?

Any advice is very much appreciated.

Thank you.
 
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  • #2
StealthRay said:
I thought of using phototransistor because i saw some receiver circuits using it. My problem is how do I amplify the signal to 24v so that the PLC can recognize it. Is phototransistor works the same way as the transistor?Is the calculation similar in obtaining the Ic, Ib, and Vce?

Yes, except that there is no Ib as it is controlled by incident light.
 
  • #3
Here's a little application note for common collector and common emitter photo transistor circuits: "www.fairchildsemi.com/an/AN/AN-3005.pdf"[/URL]
 
Last edited by a moderator:
  • #4
Thanks alot.
 

1. What factors should be considered when selecting infrared components?

When selecting infrared components, it is important to consider the wavelength range, sensitivity, and noise characteristics of the component. Other factors to consider include the operating temperature range, power requirements, and compatibility with other components in the system.

2. How do you calculate the wavelength of infrared light?

The wavelength of infrared light can be calculated using the formula λ = c/v, where λ is the wavelength in meters, c is the speed of light (3 x 10^8 meters per second), and v is the frequency of the light in Hertz.

3. What is the difference between infrared detectors and infrared emitters?

Infrared detectors are used to detect infrared radiation and convert it into an electrical signal, while infrared emitters generate infrared radiation from an electrical input. Detectors are commonly used in applications such as temperature measurement and remote sensing, while emitters are used in applications such as infrared heating and communication systems.

4. How do you determine the sensitivity of an infrared component?

The sensitivity of an infrared component can be determined by measuring the smallest amount of infrared radiation that can be detected by the component. This is typically expressed in terms of the minimum detectable signal or noise equivalent power.

5. What are common types of infrared components?

Common types of infrared components include photodiodes, phototransistors, thermopiles, and pyroelectric detectors. Infrared filters, lenses, and mirrors are also commonly used in conjunction with these components to manipulate and focus infrared radiation.

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