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Build a Square Wave Oscillator - Part 1 of DIY Modular Synths

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Step 4: Lay Out and Solder Circuit

Picture of Lay Out and Solder Circuit
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This next step requires the most skill out of the others, namely the ability to read a schematic and the ability to solder. Both have an incredible amount of resources both on and offline, so even if you aren't the most technically minded, you should be able to learn both incredibly quick. One that I would suggest is Sparkfun's "How to Read a Schematic."

Above is the schematic used for the square wave oscillator. If you're unfamiliar with schematics, it may look daunting, but take some time reading up on schematics and you'll be able to put together this circuit rather easily.

Note that I have also included a pdf version of the schematic, in case the first one is hard to read in your browser.

If you've never soldered before, I would suggest testing out your skills on a couple of extra wires and components before you try your hand on your actual circuit.

Also, I would suggest getting a "Breadboard," which is a tool that allows you to lay out a circuit and test it before making anything permanent. The second image above is an example layout of the breadboard that will work. Because breadboards are designed to be easily changed and are for prototyping purposes only, your breadboard will probably not look exactly like the one shown here.

If you're new to breadboarding, Sparkfun.com has a really great tutorial to check out.

After you've assembled your circuit, you need to transfer it to the "Perf" Board to be permanently soldered on. Take your time with this step and make sure that all of the connections are correct and that no excess wires are touching.

When you're ready, solder all of the points, and then cut all of the excess wire off. Shown above is the Perf Board, both soldered and unsoldered.

 
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gavox3 years ago
Any chance of getting a clearer schematic? can't see a blind thing on this one...
dnhushak (author)  gavox3 months ago

Three years later haha. I just updated the schematic on here to be much clearer.

dnhushak (author)  gavox3 years ago
http://www.instructables.com/files/orig/FG9/MG8C/GFRWMNFA/FG9MG8CGFRWMNFA.png

That should work.
bengoza2 years ago
Where are those jumper cables connected to? What is their purpose? Thanks for your patience, and thank you for this instructable!
dnhushak (author)  bengoza2 years ago
Which jumper cables are you referring to?
amruth3 years ago
HI, i like ur circuit and i would like to know the minimum and maximum frequency it can create. Thx in advance
I'm confused; my friend and I went by the image not the schematic (as we are 13 and have no prior training in PCB), how do you connect the potentiometer/ LED/ 9v/ input? also we wanted to add an output, how would we do that?
I meant connect output; add input
dnhushak (author)  allnighterco.3 years ago
Not really sure how to answer your question; do you want to add an input that goes straight to the output, or have it altered in some way? Also, to attach the Potentiometer/LED/9v, you just use longer leads to go from the component/jack to the right spot on the PCB.
A.Kahn3 years ago
Hi! I got a little newbie question. Im using a electrolytic capacitor, for the 100uF, and they need to be placed in the right way according to + and -. I confuse myself everytime i try to figure out which way it should be placed... So if you could tell me how the capacitor should be connected i would be very happy!
dnhushak (author)  A.Kahn3 years ago
It shouldn't matter too much, but place the positive end (the longer lead) towards the 500Kohm potentiometer, and that should work.
Can I use a 9V battery instead of a jack? That way I can get more potability out of it.
dnhushak (author)  darthpotato14 years ago
Yep. Schematic reads exactly the same.
xavseg4 years ago
Hi, i don't understand the schematics, where does the +4.5V and -4.5V go? and is it possible to make a bigger and clearer scheme?
Thanks
Sorry for my english
dnhushak (author)  xavseg4 years ago
Click on the little "I" in the top left corner of the image, and then click "view original file." Instructables just displays it weird.
oligore xavseg4 years ago
It's hard to see but I think they connect to the corresponding voltages on the connections from the op amp
The -4.5 volt connects to the ground symbol. and the +4.5 volts is connected to the words "+4.5v" on the schematic. your English is fine
Yeah, a bigger schematic would REALLY help, I cant really see what anything is saying...
dnhushak (author)  darthpotato14 years ago
Click on the little "I" in the top left corner of the image, and then click "view original file." Instructables just displays it weird.
Thank you beyond belief