Hey guys,

I dont really know where to post this, but i'm currently doing my FYP. My title is Tunable Sound Emission Unit. I have the circuit design ready and the circuit works fien a breadboard as ive already tested with a digital OSK. But i'm having trouble getting it to work on a stripboard. I'm a really poor solderer as i have very little practice with it.

I was wondering if you guys know anyone i can ask to solder the circuit for me. Its a really simple circuit with only 3 IC's. I'd gladly pay good money to anyone who can help me. So if ur interested or u know anyone who wants to make a quick buck, please PM me ASAP. Your assistance is much appreciated. Thanks !

This post has been edited by haflife: Apr 12 2007, 01:17 AM

imma now building amplifiers and other destructive thinggies. Finished my FYP sometime back, it was a simple DAC circuit for compressive audio encoding. Now i'm going back to simple hobbist circuits.

Could you just post some images of your work so maybe someone here can help you troubleshoot.

you guys have forgotten:

http://www.edaboard.com
http://www.hackaday.com

This post has been edited by draggy: May 6 2007, 07:32 PM

Hi guys.Im a DIY know-nothing-about-how-it-works electronic fan.Just build electronic circuits for fun.

My next project is a 100W amplifier to replace my current lunch box 20W amplifier.Not to forget some new speakers.

What type of amplifier you want to build??

Im planning to build another sound stereo amplifier.

need advice here.

would it matter to replace the electrostatic capacitor with ceramic type?

and also, replace ceramic type with electrostatic...

thjanks

I guess you mean Electrolytic capacitor and Ceramic capacitor.
There is only one significant difference between these two capacitors. Electrolytic capacitor should be connected by considering its polarity (the +ve and -ve terminal) but for ceramic polarity is not important (means you can connect which way you want to connect also).

For more info :- Try wiki Electrolytic capacitor

some say ceramic capasitor has better noice filter effect...?
would this affect my amplifier?

thanks

As in mathematically speaking, ceramic or electrolyte capacitor, we are just concerned about its capacitance, thats all.
Usually, in fact most of the time ceramic capacitors are lower capacitance.
So in that case, with low capacitance, high frequency signals can be filtered well (because the impedance of the capacitor will be large).

I would caution againts using that line of thought because real capacitors have ESR, DCL, Tangent Angle loss, PPM temp deviation and stability and many other specs such as noise. So it very much depends on where you're using it.

I tried to build a crystal radio before, it was fun, but kinda hard to get material from here.. I once asked the electronic shop owner about magnet wire, he told me he don't know what is it.. swt My dad have to go out station to buy those stuff for me..

Any 1 know where to find electronic stuff around KL/ Selangor?

jalan pasar ?

As you saying, it is very much depends on where you are using the capacitor.
As for simple audio applications, we do not need to be very particular, as the noise tolerance is limited by the user itself.
Of coz in high precision circuits, other factors such as temperature should be considered.

Yeah,thats about the only place that sells electronics.

Not really, for audio circuits, ESR can combine with Series resistance to form an LP filter of sorts and having a knee too early isn't exactly good, you might cut out or attenuate higher order frequencies. Plus electrolytics aren't linear enough for anyone's liking in audiorange when placed in the signal path, and they tend to skew frequency response, especially cheaper ones.

Plus there is a chance of miscalculating feedback depending due to cap constraints.

What type of capacitors you usually use in your design (i mean amplifiers)?

For capacitors in the signal path, i'll stick with metallized film polyprolene or polyphenyl sulphate caps, although i will go to Polyester and if forced to, then ultra high quality electrolytics. If possible, and if i can keep the offset low enough by properly tuning the power supply, i won't even use caps at all. But then again, they're like condoms, they give you that extra safety net if shit happens, but it's always not as good as just sticking it without one.

For filters, i prefer Silver Mica, i also like it for ground decoupling due to it's somewhat better characteristics in the stability domain. I also use Ceramics when decoupling ground to V+, i use values depending on the frequency of the noise i want to hammer out, but i like .1 uF as my standard.

For the power supply, i use Electrolytics as the main filter and capacitance tanks. For bypassing and snubberizing, i use high voltage self healing films since they work well with high frequency pulses and can help stop EMI and RFI from penetrating the design. And last if not least, tantalums for regulator stability.

I have developing a line following robot. The schematic can be found in this page.

http://www.james.vroman.com/javbot1a.htm

I didn't not build the exact circuit but some parts of it i left it out. I did not include the multiplexer 74HCT138 and comparator LM311. What i did is only using a IR sensor a H-bridge and a motor.

I have tested the IR with a LED replacing the motor and it works. Whenever i replaced the motor back, it won't turn. The battery i am using is that square sized 9V battery. The MicroC i am using is 16F84A. The motor i am using is slightly larger than ordinary tamiya motor; a round shaped motor.

I even tried using a smaller motor(i think they call it micromotor and the size is smaller than ordinary tamiya motor) but the same thing turns out. I also tried using op-am 741 to amplify the output voltage but nothing happen.

I tried operating the op-am on a separate circuit using whatever kind of configurations. Without load, the amplification works perfectly but when i connected it with the motor, it screwed up. Anyone can give me ideas to deal with the problems?