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Welcome to CHM

Circuit Hacking Monday

by “J”

@CircuitHackingJ

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This class and this space are made possible by contributions of people like you.... Which also includes helping cleaning and organizing the space

Thank you!

Donate.noisebridge.net

(Say that is for CHM)

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Remember

Do not think of me as a teacher, more like a guide or point person

Think about doing presentations, running a class. Always learn from each other.

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Why come here?

Can I use some of the stuff I learn here in my life?

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Last time: the multimeter

The multimeter is an essential tool for working with electronics and circuits. It can help test, troubleshoot, and help understand electronics.

Remember the word “circuit” comes from the word “circle”

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Here is how you test it:

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Here is how you test it:

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Review: schematics

Schematics might seem scary but they are just a picture representation of how the components are connected together to make a circuit.

Remember the word “circuit” comes from the word “circle”

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We will get to build this...

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And today we are looking into one of its components

The Capacitor

What does it capacitate?

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This is a capacitor

What and why:

Think of it as a small battery
It holds a charge until needed
It helps prevent odd bugs that are normally tied to high load as the voltage really sags

(sags means that voltage goes below what it needs to be).

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Here is an example of noise from a mic and amplifier

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In other words...

If all you wanted to build was digital circuitry, and your voltage sources really held constant voltage no matter how much current was drawn from them, and nothing produced electrical noise, you wouldn't need capacitors.��But voltage sources sag when you draw current from them. Motor brushes (and lots of other components) produce horrendous voltage spikes that you want to filter out of your digital circuitry.

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This is how it was fixed

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You just have to play with it

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Let’s charge the capacitor

Let’s test the components!

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Now just watch it discharge. Look at it carefully, it goes by fast!!!

Let’s test the components!

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Set up your board like this and use the multimeter to see changes.

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Now try to add some resistance and see what happens.

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What is time capacitance?

capacitance�noun PHYSICS�

The ability of a system to hold an electric charge.

The SI unit of capacitance is the farad (symbol: F), named after the English physicist Michael Faraday

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Voltage, Resistance, and Capacitance

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Michael Faraday

Received little formal education.

He educated himself as he was working as a bookbinder.

Contributed in the study of electromagnetism and electrochemistry

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What is The Time Constant?

A way to predict exactly how much it takes for various capacitors to charge when they are paired with various resistors.

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Official explanation requires differential equations

time constant�noun PHYSICS�

A time that represents the speed with which a particular system can respond to change, typically equal to the time taken for a specified parameter to vary by a factor of 1- 1/ e (approximately 0.6321).

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“Math will draw the soul towards the truth”

-Plato

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You can get something like this

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Donate $20, keep the project and get all of this!

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List of Components

1x Breadboard�20x Jumper Wires�1x SuperBright 5MM IR LED 940 nm�1x IR Sensor TSOP38238�3x 2N3904 NPN Transistors�3x Diodes 1N4007 Diode�3x Potentiometers�5x Pushbutton Switches�1x Piezo Buzzer PS1240�1x Super Fantastic 8MM RGB LEDs�5x Blue 3MM LEDs�5x Red 3MM LEDs�5x Green 3MM LEDs

1x Photoresistor�20X 220 Ohm Resistors�20X 330 Ohm Resistors�20X 1K Ohm Resistors�20X 10K Ohm Resistors�20X 10 Ohm Resistors�20X 47 Ohm Resistors�1X Vibrating Pager Motor�

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Donate an additional $5 and get a new multimeter. ($6 by itself)

Some of what it measures:

DC Voltage
AC Voltage
DC Current
Resistance
Diode and continuity
Transistor test��

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Important Links!

http://tinyurl.com/CHM-Presentations

http://tinyurl.com/CHM-Videos

https://noisebridge.net/chm

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Please donate to the class