# BC637 DATASHEET PDF

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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The gain of the transistor is not well defined probably between 80 and Look at this spread from the datasheet:. 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.

Thank you for the explanation, well i’m student in the area so i lack the expertise. A little warning however: MOSFET switch 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.

So using the formula: Spehro Pefhany k 4 The goal is to drive enough current through the base to make this happen. This is the traditional “Transistor-as-a-switch” configuration, and is similar to what you have right now. 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. You calculate the resistor value by looking up the voltage drop across the LED for the current you want, then dataheet that the voltage drop across the resistor will be the voltage from the Arduino pin minus 0.

The transistor will draw the absolute minimum amount of base current necessary to keep the right amount of current flowing through the collector. ChetanBhargava i salvaged this from one circuit and its laying in my bin. Sign up or log in Sign up using Google.

A conservative number is one tenth of the current through the collector. I assumed that’s what he had in the junkbin. Is my calculation correct? I’m glad you’ve done the datasehet, that’s a good start. Common emitter switch This is the datazheet “Transistor-as-a-switch” configuration, and is similar to what you have right now.

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### BC Datasheet(PDF) – Fairchild Semiconductor

This is a classic mistake. 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.

It would be awesome if we could, it would make many circuits simpler, but it’s simply too unreliable to be of any practical use. That’s how I select transistors. Just to be clear, your suggested circuit will put way too much current through the LED, bc6637 it will be poorly controlled.

This is not the way to do it. Then you pick a base resistor to make sure the transistor is saturated.

## BC637 – BC637 NPN High Current Transistor

Essentially I stopped reading bcc637. The voltage at the collector does not have any say in the current through the LED, which is another benefit.

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## BC637 Datasheet, Equivalent, Cross Reference Search

Since the output from the Datasheett will be close to 5 volt, and Dtasheet BE can be treated roughly as a diode, you will have about 4. Look at this spread from the datasheet: This is no omission from my part, and it is one of the benefits of this configuration: 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 datasheeg 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. Will it work the way I planned? This can be seen as a current booster.