Datasheet of 2N It is apparently a visible light phototransistor (also includes IR since no IR filter is indicated) –no wavelength is indicated. PHOTOTRANSISTOR. Part Number: WP3DP3BT. Features. ○ Mechanically and spectrally matched to the infrared emitting. LED lamp. ○ Blue transparent lens. The circuit you show should work as it is, since it is already for a phototransistor. Just leave your base lead floating. EDIT – the breadboard.

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These photo transistors generally use a mesa structure. Heterostructures that use different materials either side of the p-n junction are also popular because they provide a high conversion efficiency. If the base connection is required, then it is necessary to buy a phototransistor with a base connection available.

R1 will limit that. When you buy electronic components from 1-Source you can be sure you are getting only the best parts at the best prices. The phototransistor base is floating, and I swapped the 1k for a 22k in my circuit to bias it correctly I arrived at this value roughly, see below and used a BC npn.

Phototransistor Circuit Configurations | Applications | Electronics Notes

The collector is taken to the supply voltage via a collector load resistor, and the output is taken from the collector connection on the phototransistor.

Here is the link but I am using photo-transistor but this circuit is for LDR, so how can I use photo-transistor in this circuit? We are a franchised distributor of electronic components, as well as a sourcing and procurement agent for hard-to-find, obsolete, and allocated parts. Supplier Directory For everything from distribution to test equipment, components and more, our directory covers it.

Phototransistor operation The phototransistor uses the basic transistor concept as the basis of its operation.

Build More-Effective Smart Devices: It was then only two years before the photo transistor was demonstrated. Phototranssitor if Q2 the phototransistor gets light it will also draw current, and draw it away from Q1.

Common base circuits are not normally used because the base connection is often left floating phototraansistor and may not be available. Phototransistor symbol The phototransistor symbol for use in electronic circuit diagrams is very straightforward. Common emitter phototransistor circuit The common emitter phototransistor circuit configuration is possibly the most widely used, like its more conventional straight transistor circuit.


Security systems – phototransistor can be used in many ways in security systems, often detecting whether a beam hpototransistor light is present or has been broken by an intruder. Power Transistors RF Transistor. Is it possible that your phototransistor gives you a base connection to allow you to bias the transistor and then use the light to increase on top of a DC large signal Bias?

The circuit actually acts as an amplifier. Sign up using Facebook. Steven – In general yes, but we’ll have to agree to disagree on this one I think: Maybe change the resistor to 2k or larger if you are worried about blowing the LED.

The phototransistor can be used in a variety of circuits and in a number of ways dependent upon the application. The choice of common emitter or common collector phototransistor circuit configuration depends upon the requirements for the circuit.

The site you got the above circuit from also has an example of such a circuit: The common collector, or lhototransistor follower phototransistor circuit configuration has effectively the same topology as the normal common emitter transistor circuit – the emitter is taken to ground via a load resistor, and the output for the circuit being taken from the emitter connection of the device.

t2 2n5777 ir photo transistor Inventory Search Results*

The physical gap between the light emitter and detector provides a considerable degree of electrical isolation. You can leave the base floating unconnected or connect it to ground through a resistor.

The switch mode, therefore has two levels: 2n5777 and warehousing available. We are well known for our great prices, great selection, and as the leading online source for hard-to-find and hard-to-buy electronic component parts. Can you please show a picture or something, I am a newbie and can’t really understand your explaination. First move the LED to the transistor’s collector, and add a series resistor.


Hetero-junction devices have a much higher limit and some can be operated at frequencies as high as 1 GHz. The circuit symbol also has the convention arrow and directions on the emitter connection. In any case he has plenty of info about both versions now: Latest news LoRa technology integrated in utility metering solution Four-in-one environmental sensor saves space and power MACOM debuts new ultra low phase noise amplifier Ericsson and Panasonic Avionics bringing connectivity to the skies Beeline chooses Broadpeak Solutions for TV Everywhere service.

William Shockley first proposed the idea innot long after the ordinary transistor had been discovered. The two phototransistor circuit configurations have slightly different operating characteristics and these may determine the circuit used.

The circuit actually acts as an amplifier. The base is at 0. This is set by estimating the maximum current anticipated from the light levels encountered. The reason the circuit is usually not the best way to do this is because it relies upon Hfe, which can vary quite widely in a transistor and is subject to temperature changes.

Since the BC has lots of gain the 22k works well for the base current. Since then phototransistors have been used in a variety of applications, and their development has continued ever since. Umer – I added a schematic and edited the text.

Phototransistor Symbol and Circuit Configurations

It can be seen that the phototransistor symbol shown does not give a base connection. The circuit generates an output that moves from a high voltage state to a low voltage state when light is detected.

If phototransistor Q2 does not draw current, then Q1’s base gets current through R2. Like more conventional transistors, the phototransistor can be used in common emitter and common collector circuits. This is set by estimating the maximum current anticipated from the light levels encountered.