BC, BC, BC High Current Transistors NPN Silicon Features. Base NPN Epitaxial Silicon Transistor Absolute Maximum Ratings Ta=25 C unless otherwise noted Symbol Parameter Value Units VCER Collector-Emitter Voltage at RBE=1K? : BC 45 V: BC 60 V: BC V. BC BC VCEO. Vdc. Collector – Base Voltage. BC BC BC VCBO dimensions section on page 4 of this data sheet. ORDERING. DATA SHEET. Product specification. Supersedes data of Apr Oct DISCRETE SEMICONDUCTORS. BC; BC; BC

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Since the output from the Arduino will be close to 5 volt, and V BE can be treated roughly as a diode, you will have about 4. By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policybc67 our Terms of Service.

A circuit that relies on a specific current gain will simply not work well.

BC Datasheet(PDF) – Fairchild Semiconductor

Bc63 as switch with Arduino Ask Question. It is better to add a series resistor on the LED – the forward voltage of a blue LED is probably around 3V, so the resistor drops 2V and at 22mA it would have to be about 91 ohms. This is no omission from my part, and it is one of the benefits of this configuration: Essentially I stopped reading there.

The series resistor at the gate is there to limit the switching current, and the resistor from gate to ground is there to make sure that the gate is not floating while the pin is in b637 high-impedance state that is, an input or turned off. That’s how I select transistors. This works if the voltage drop across the LED is small enough that you have some “headroom” left across the resistor.

The gain of the transistor is not well datasheeh probably between 80 and Post as a guest Name.

(PDF) BC637 Datasheet download

dataseet You calculate the resistor bc6377 by looking up the voltage drop across the LED for the current you want, then observing that the voltage drop across the resistor will be the voltage from the Arduino pin minus 0.


Essentially you’ll use one of these circuits:. Post Your Answer Discard By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies. I’m glad you’ve done the calculations, that’s a good start. By datasheeh “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies.

A forced beta of 20 is usually good. As you can see, there is no base resistor.

Look at this spread from the datasheet: I don’t have much experience with electronic components, and I would like to ask someone with more experience than me to check if my calculation is correct.

This is perhaps the easiest to understand, because it’s as intuitive as the common emitter switch, but you only have to calculate the load resistor. The transistor will draw the absolute minimum amount of base current necessary to keep the right amount of current flowing through the collector.

This is not the way to do it. The voltage at the emitter will closely track the voltage at the base, only 0. Is my calculation correct?

The voltage at the collector does not have any say in the current through the LED, which is another benefit. Then you pick dataasheet base resistor to make sure the transistor is saturated. Essentially you’ll use one of these circuits: If your board has an unregulated input with a lot of ripple, you can use it directly.

Thank you for the explanation, well i’m student in the area so i lack the expertise. If the 5V rail drops before the power to the Arduino, perhaps if they are powered from separate rails, all the current to the LED will come from the base, and thus from the Arduino. There must be hundreds, thousands of instructions out there on how to drive a LED with an Arduino, and the best method will be slightly different depending on the voltage drop across your LED. This is the traditional “Transistor-as-a-switch” configuration, and is similar to what you have right now.


The goal is to drive enough current through the base to make this happen. ChetanBhargava He’s reading the minimum hFE, it goes up to Just to be clear, your suggested circuit will put way too much current through the LED, and it will be poorly controlled.

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Common emitter switch This is the traditional “Transistor-as-a-switch” configuration, and is similar to what datasyeet have right now. A conservative number is one tenth of the current through the collector.

It would be datsaheet if we could, it would make many circuits simpler, but dagasheet simply too unreliable to be of any practical use. I’d sure like to see the documentation that claims this is the recommended value. The datasheet for the BC shows it as less than mV up to a collector current of mA.

Look at this spread from the datasheet:. Spehro Pefhany k 4 Email Required, but never shown. I assumed that’s what he had in the junkbin.

BC637 – BC637 NPN High Current Transistor

Sign up or log in Sign dagasheet using Google. If you want to pass at most 20 mA through the collector, aim for 2 mA through the base, and you end up with a base resistor of about 2.

The idea is however that the Arduino should drive the transistor fully on so it’s saturated, passing as much current as it can, or at least enough so that the transistor is not the limiting factor. So using the formula: