Show Posts
Pages: 1 ... 3 4 [5] 6 7
61  Forum 2005-2010 (read only) / Interfacing / Re: Questions about transistors, capacitors and diodes on: January 22, 2009, 12:22:21 pm
thank you...

I have yet another question. Since my first thought was to buy the more capable transistor of the three and also the most expensive one, not that price really matters since I'll be buying only 5 pcs, however I just want to get my head around this. In my list I already have a higher current capable darlington transistor. I could use this one for whatever might need more than 100 mA and go with any of the cheaper transistors under 100 mA.

This is the first time I'm buying transistors and using them, hence the many questions.

62  Forum 2005-2010 (read only) / Interfacing / Re: Questions about transistors, capacitors and diodes on: January 22, 2009, 12:42:47 am
@Anachrocomputer
Yes I am...

@drspectro
Great tip... Btw how about a good PNP equivalend to BC547B (I realized a mix of transistors would be cheaper than buying just the high current ones).

63  Forum 2005-2010 (read only) / Interfacing / Re: Questions about transistors, capacitors and diodes on: January 21, 2009, 02:46:34 pm
... or I should just learn math better. Turns out they were labeled 100 nF instead of 0.1 uF.
64  Forum 2005-2010 (read only) / Interfacing / Re: Questions about transistors, capacitors and diodes on: January 21, 2009, 02:40:24 pm
Thanks!

The BC547 is the cheapest of the bunch but since it's got a 100mA rating I'll go with the 2N2222A since I might need more juice driving multiple leds and whatnot.

65  Forum 2005-2010 (read only) / Interfacing / Questions about transistors, capacitors and diodes on: January 21, 2009, 02:15:31 pm
I'm putting together a shopping list of components for general purpose use. Some of them from a post I made in this forum, some from Tom Igoes "Making Things Talk" and some from tutorials I've found online describing different stuff.

However I have some questions....

Capacitors: My retailer only carries electrolyte 0.1 uF. Can I buy that instead of ceramic?

Transistors: I'm only trying to buy some generic stuff in a batch not for any specific projects. And to me the first three on the list look pretty much the same. Can I exclude two of them or could there be other differences I need to consider? If I can, could I do without any of the others aswell?

   1. 2N3904 TO-92 NPN 50V 100mA
   2. 2N2222A TO-92 NPN 40V 800mA 300MHz
   3. BC547B TO-92 NPN 45V 0.1A
   4. TIP120 TO-220 NPN Darlington 60V 5A
   5. IRF540 TO-220 N-ch MOSFET 100V 28A
   6. 2N3906 TO-92 PNP 40V 200mA

Diodes: Same question as above...
   1. 1N4004 DO-41 400V 1A
   2. 1N4007 DO-41 1000V 1A
   3. Zener BZX55C3V3 DO-35 3.3V


Best regards
Makkan

66  Forum 2005-2010 (read only) / Interfacing / Re: A call for a list of basic electronic components on: January 13, 2009, 02:50:13 pm
To bad none of my vendors here in sweden had that box. Then again they seem to be sold out in the US aswell.

Good tip though..
67  Forum 2005-2010 (read only) / Interfacing / Re: A call for a list of basic electronic components on: January 13, 2009, 09:57:28 am
great thanks!

68  Forum 2005-2010 (read only) / Interfacing / Re: A call for a list of basic electronic components on: January 13, 2009, 09:07:51 am
thanks alot...
However as I have no clue what a general purpose transistor or signal diodes would be.

With the resistors you mean 470 Ohm and 4700 Ohm right?
69  Forum 2005-2010 (read only) / Interfacing / A call for a list of basic electronic components on: January 13, 2009, 07:25:44 am
As each day goes by I learn more about the arduino and electronics and for each thing I learn I quickly realize that I don't have this or that component to make practical use of my new found knowledge.

When I bought my arduino I sort of had a clue that I would run into this so I stocked up on what's in the adafruit Arduino starter kit.

I got the following:
Resistors (100, 1k 10k Ohm)
Potentiometers (1k and 10k Ohm)
2 Tactile push buttons
2-5k Ohm CdS resistor
1 of each red, green, blue high power LED
5 diffused red leds

Other stuff I had lying around from before:
1 DC motor from an electric tooth brush (I can slaughter the other tooth brush aswell for another motor).
An assortment of leds in various sizes, shape and colours.

And thats about it!
Oh, I know I should get a L293D H-bridge for running the DC motor. But I probably won't stop there I probably also want to try using a servo, stepper, piezo and so forth...

So before I go and order the H-bridge can are there any generic components I should consider buying?
There seem to be about a thousand different types of capacitors, diodes, transistors, mosfets and whatnots... and I haven't got a clue as to where to begin.
70  Forum 2005-2010 (read only) / Interfacing / Re: Getting data from a salvaged DC motor on: January 13, 2009, 03:36:59 pm
I've done some additional measuring and have the following data:
0.5A @ 3V with original load but the motor fails to rotate
1.02A @ 9V with original gear load
0.7A @ 9V without load

3V comes from two 1.5V C type batteries in series and 9V from a single 9V battery.

@brum
Could it be our tooth brushes differ somewhat since my motor wont even spin when in the original geared load? Or is it so that a Ni-Cad battery can provide more current?

71  Forum 2005-2010 (read only) / Interfacing / Re: Getting data from a salvaged DC motor on: January 13, 2009, 07:42:01 am
Ok,

I'll try an hook it up to a 9V battery and se if I get similar results.
72  Forum 2005-2010 (read only) / Interfacing / Re: Getting data from a salvaged DC motor on: January 13, 2009, 01:10:38 am
Actually I put one load of 1.5V and one load of 3.0V and got about 0.5A of current on both.

This was without any mechanical load what so ever. I realize now that I will have to measure again with a known load and perhaps give a litte extra room for mechanical overload.

One more question, lets say i connect a 9V battery to the DC motor, could I damage it in some way or is it just going to run faster with a higher torque. As if more power = more power?


73  Forum 2005-2010 (read only) / Interfacing / Re: Getting data from a salvaged DC motor on: January 12, 2009, 05:37:24 pm
thank you... allthought I already knew about those pages. What I want to know is if I did a correct measurement of current running trough the motor.
74  Forum 2005-2010 (read only) / Interfacing / Getting data from a salvaged DC motor on: January 12, 2009, 02:55:49 pm
I had a pair of old Braun Oral B electric toothbrushes lying around that I decided to gut. Among other things I found a DC motor I was hoping to use with my arduino. But from what I've read it's possible to damage the arduino with currents bigger than 20 mA, DC motors being mentioned as having larger currents.

So I decided to measure the current of my salvaged DC motor. I hooked the motor up to a 3V and 1.5V battery and my multimeter in series. What I got was 0.5 A. For me this seems good I just want to know if I did it right.

 


75  Forum 2005-2010 (read only) / Interfacing / Re: Arduino power and ground questions on: January 13, 2009, 10:38:09 am
Thanks for that link.. it seems to answer all my questions.
Pages: 1 ... 3 4 [5] 6 7