Transistor Amplification - Arduino Workshop Project Video #2

[kennyfication88]

Hey Guys, I need this method to amplify a microphone. The Mic uses about 20µV and needs to be amplified for use with the arduino. Can somebody tell me how to connect everything? Thanks :)

[kennyfication88]

Thanks man, you helped me a lot.

[WarSpigotProductions]

Diode:$0.15(~.03 on eBay)

Transistor:$.75(~.03 on eBay)

Arduino Motor Shield:$24.99

This Video:priceless(actually, it does have a price -- $0.00)

[bluemarvel5]

Do you have the data sheet for the motor because I think it is a 3V motor.

[Halo2maniaccc]

This motor came from a little robot kit. It had 4 AA batteries powering it so I am assuming the motor is rated for 6v. Most of these little motors can take 3 - 9v without any real problems it just that a higher voltage with increase rpm and heat. That will reduce motor life. As to how much current it draws or any specs I don't really know it was just a little motor I found for use in the video.

Hope this helps!

[Halo2maniaccc]

Yes that is entirely possible you would just have to select a transistor capable of pulling the amount of power your led's will draw. Datasheets for the led's will tell you how much each will draw. Then you would have to get a resistor rated for the correct wattage (one big one) or you could split it up (1 per led, 1 per group of 10 ect...).

Big transistors need a good deal of juice to turn them on so you may need a 2nd tiny transistor to pre amplify the arduino signal.

Hope this helps!

[AKSoapy29]

Where did you get the breadboard?

[Halo2maniaccc]

I don't remember exactly just look around this is a pretty common model. I don't even use this anymore my new breadboard is 6 of these put together its huge got it for $30 on ebay.

[emihackr97]

te chip has an output of 40 mA per pin and a total of 920mA max!

[jn777]

@Halo2maniaccc thanks for your answer I took the time to read about it and I got your point, it acts as a switch because it is at the saturate region and can't amplify more. Keep the good work with the videos I like them, regards!

[jn777]

Really Nice video, but the transistor is not really amplifying, the transistor is acting like a switch controlled by the digital pin out.

[Halo2maniaccc]

The transistor is an amplifier, it takes the small signal from the digital pin and has a gain on it. If you check the packaging it will tell you what the gain is typically its around 100 alot of people call it the amplification factor. When the transistor is energized in this circuit it acts as a switch but seriously google around for other little projects. I did a few of them and learned a tremendous amount about transistors, they are anything but simple switches.

[Halo2maniaccc]

What I meant was that in this circuit the signal is amplified from the digital output pin its not just a switch there is amplification involved. With a gain of 100 I can put 1milliamp in and get about 100 out. So this switch is not really just an open/close switch the larger the amount of current from the digital output pin the more current that can flow to the device (amplification).

[1world1love2day]

@jn777 youtube.com/watch?v=ZaBLiciesO­U <note at the end where he mentions a transistor can be a powerful amplifier

[arduino02]

Would this circuit work with a fan and a temperature sensor

[Halo2maniaccc]

It depends on exactly what type of fan your dealing with. There are much more advanced higher end pc fans today that have integrated speed controllers. Those are really easy to set up you just give it power, a pwm signal and your good to go. If you have just a regular old fan with power input then you will need a circuit like in the video to control it. Make sure you use the circuit with the diode as it is an inductive load.

The temperature sensor has nothing to do with this that is separate

[AKSoapy29]

How did you do the PWM of a motor? Can you PM me the code? Cause I can't get it to work.

[Halo2maniaccc]

You don't use PWM like you would for a servo. You have to use digitalWrite in arduino on the pwm pin. That will create the speed control you want. Also you could hook it up to an analog pin and try analogwrite. I don't have the code for it but if you google for examples of analogwrite/digitalwrite you will find a few examples.

[AKSoapy29]

And do I have to use the 2N2222 or can I use a different one?

[Halo2maniaccc]

You can use any standard npn transistor the 2n2222 just happens to be easily available at radioshack.

[sinnerrom]

hello

instead of the Arduino power source can be used to connect to another power source? and which is the maximum and minimum volts and amps of that? thanks

[Halo2maniaccc]

Yes you can hook up an external power source to it as long as the arduino is connected to ground. It doesn't have a set power rating it depends on what transistor you use some can handle small loads while others can handle massive loads. This transistor can work up to 36v. Look up the datasheets for these transistors they will tell you all you need to know.

[tiputipu0052]

hi, can you tell me for building a AM transistor radion, if i want to use 2 transistors as darlington...then use amplifier for further amplification... ,,what should be the value of bias resistor(collector. base)in darlington.....i usually use bias resistor 100k for single transistor ...similarly if i use 3 transistors as darlington..what should be the bias resistor..similarly if i use 4..5..6...

[samtheman1993388]

So by using this circuit what is the max load that you can power? I am guessing 5v as that is what the Arduino board runs at?? Also can you remember the voltage of that motor?

[Halo2maniaccc]

The motor was pulled from a 6v rc car so I would assume its rated for between 5v and 7.5v to be safe. The max load of the circuit isn't based on voltage, instead its watts (voltage x current). There is a max voltage of about 30v for that transistor but it can only push about 600mw so the current would be low. So the circuit doesn't have to run at the running voltage of the arduino which allows a world of possibilities.

[dodgedart74]

very stupid question but, ive just been using LEDs for my diodes, that has no long term effects does it?

[Halo2maniaccc]

An LED is still a diode so I would assume that it SHOULD work. I would ask someplace like 4hv because I don't really know every difference between the two. My personal suggestion would be to just get the proper diodes from radioshack or online.

[herctrap]

can we use a mosfet?

[herctrap]

@herctrap

we can use it

but how we can?

[edicus25]

Great video, but what are the pins for the transistor? I looked for the data sheet on the Radio Shack web site and couldn't find it.

[Halo2maniaccc]

The transistor I used in the video has the same pin out as the one from Radioshack. Look at the flat and convex side of the transistor in the video.

I don't know why Radioshack doesn't have them online but the diagram will be on the back of the package that they come in. It has tech specs about it as well as the basic pin out.

Make sure you use the 2n2222 transistor because that "pack" of 15 only has 5 of them, the other 10 are different types. They will work but have different power ratings.

[TheTubejunky]

@Halo2maniaccc

!NOTE!: That the RadioShack packaging specs (on the back of the package) are sometimes incorrectly labeled, Just go to radioshack's website and look @ the review/comments about the transistor (or component) in question.

I suggest googling the datasheet before trusting radioshack's package specs.

[hasnachos]

wow i ad no idea what a transistor was or did, but now i see what its for... and the white circuit thing where you plug everything into, where can you buy one? would one of those work for programming a set of leds that can strobe in various blinking patterns?

[addzkebabs]

your a goose, but anyway your get a braed board(white thingy) from any electronics store!

[Halo2maniaccc]

The white board with all the holes in it is called a breadboard. It is used for rapid prototyping of circuits. You simply put component's on the board and use wires and things to jump power around. This is a MUST HAVE and yes it will work for those LED's. The blue circuit was the programmable part the white board was only for connecting it all together!

You can get them at Sparkfun or ebay just search for "breadboard". The ones on ebay are just huge w/ free shipping for a really low price!

[Halo2maniaccc]

O yea thanks to addzkebabs I just remembered that you can get them at Radioshack if you really need to go local or sometimes at hobby shops.

However I would recommend that you DON'T go to Radioshack. It may be convenient but they will charge you like $20 for a breadboard that is slightly larger then the one in the video. If you go to ebay you can get one that is like 6 times larger, w/ free jumper wires and shipping for around $18!

[st1gma888]

Good stuff man.

[Halo2maniaccc]

Thanks

[UserIsAnFBIAgent]

Thats pretty cool stuff man, thanx allot.

[Halo2maniaccc]

No problem!

[addzkebabs]

Awesome! um, is this going to power servo's and brushless motors (with or with out the esc attached)? thanks.

[Halo2maniaccc]

Well if you get four of these and place them in an H bridge configuration you can have bi directional speed control but only for brushed motors. For brushless I believe controlling them in more complicated so I would have to check in with that. As for servos they already have the circuitry inside, all you have to do is connect them to a power supply and send them a pwm signal.

Thanks for watching!