SQUARE WAVE GENERATOR

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Here is the schematic for my first finished signal generator! I am really excited to finish my first project within a single month! I learned LOTS of things with this project!

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COMPONENTS LIST:

9v Battery
SPST Switch (On/Off Switch)
SPDT Switch (Settings Switch)
MOM (ON) Switch (Push to Make)
IC1 - 7805 5v Regulator
IC2 - 40106 Hex Inverter
C1 - 0.1uF Capacitor
R1 - 100K Potentiometer
R2 - 100K Potentiometer
R3 - 10K Resistor
Output - 1/4" Audio Connector




HERES MY FIRST RECORDING WITH THE NEW SIGNAL GENERATOR!

SCHEMATICS

SCHEMATICS are a map of an electronic circuit. They are generally read from left to right, top to bottom, with diagram following the flow of energy through the circuit starting from the battery and flowing towards the output, which will be a speaker for our projects. Since we are going to be reading a lot of schematics, it's important to understand how to read them. Im going to redraw most of the schematics I find on the internet (and eventually draw my own schematics) to keep them consistent with how I best understand how to read them.

The various components on a schematic are labeled in the order that the current flows through them. For example, the first resistor passed will be labeled R1, the second will be R2. Every schematic has a COMPONENTS LIST to go with the schematic. This is the detailed list of parts (and shopping list!) that functions as a schematic key explaining what each component is.

Here are a few basic symbols that will be included in every schematics for my project:

This symbol represents the battery. My eventual goal is to have my oscillator powered from a 9V battery adapter, but for many of the earlier projects I will be using an actual 9V battery. The positive wire from the battery clip is red, the negative wire from the battery clip is black.

Wires are represented by straight lines. Wires may overlap on the schematics, but they are only connected if a dot is placed over the crossing point.



This symbol represents the speaker or output signal. On some of the schematics Ive been finding, they just write output, but this is confusing since every electronic component has two wires (a positive and a negative) and I want to know where the other wire goes. It usually goes in the ground. My eventual goal is to have a 1/4" output from every device, so I can connect it to an amplifier, but since I am constrained by what I know in the beginning, my early outputs are a 3.5mm audio connector, or 1/8" output.

FIRST PROJECT

This is my first attempt to create an oscillator, using a schematic that I found at hackaday.com .

ITEM LIST:

IC1 - 7805 5V Voltage Regulator
IC2 - 40106 Hex Inverter
R2 - 100K Potentiometer
C1 - 0.1uF Capacitor
9V Battery Clip
9V Battery
3.5mm Audio Connector





I built it on a solderless breadboard and sent the output signal into my keyboard amp. The finished oscillator sounded like this : listen here

Although it looks simple, it took me forever to figure out how this works. Where the schematics says IC2P, the ground from the IC2 is connected, as well as the ground from the audio connector. What also took forever to figure out was that the Voltage Regular has the three wires arranged positive, negative, ground and not positive, ground, negative as I expected.

I also dont quite understand the 7 and 14 behind the VSS and VDD. The ground on the IC2 comes from the 7 pin, but the supply comes from the 8 pin, not 14. The oscillator actually makes a different sound when connected to different pins between 8-14. Does anyone know why this is? I don't see how it changes the resistance.