Lecture Notes¶

Wednesday Neil¶

Ribbon cable - Use this instead of loose pins

Wire is specified by AWG

You can search AWG vs Current

Connectors

EDA (Electronic design automation)

How 2 pcb¶

First start sketching on paper

then create a schematic

then place components

then route wires

simulation?

fabrication

EDA¶

0 Ohm resistor to create bridges on one layer boards

DRC (Design rules check)

KiCad - One of the best pcb design softwares. Biggest limitation they are seperate programs

SnapMagic, To get footprints into kicad

schemtic -> pcb tool to lay out your schemtic physicaly

Fabrication toolkit for KiCad

Eagle is build into fusion.

https://componentsearchengine.com https://libary.io

Don't forgot an LED

Test equipment¶

Multimeter Osciliscoop Logic Analyser

Assignemnt¶

Group: Use test equipment to look a test equipment. Check voltage Check noise using Osciliscope Logic analyser to decode what its doing

Individual: Use a EDA tool to design a development board.

Extra: Simulate it. Extra: Design a case for it kicad

Thursday Erwin¶

Circuit - A circuit a closed loop where electrons can flow

Difference in electrical ptential between points sum of all coltages around a loop = 0; There is never loss in voltage Water analogy

Water definition High water fall high voltage The more water the more current

Wall sockets - AC - The polarity switches constantly DC- Always positive or negative

Tools¶

Multimeter¶

Test voltage, current, resistance Some can test capacitors.

Make sure to check where you wires are in.

Oscilloscope¶

Oscilloscope screen is a grid which each square having value. Each square can have ms in time and voltage.

make sure to connect the line you wanna test and the ground

3 Importand knobs on the oscilloscope

Amount of volts to be displayed (change volt per square)
2 buttons for each channel to change the height on the screen of the signal
Time to be displayed

Oscilloscope is used when you have a problem. When something isn't working and you don't know what.

voltage drop

always first connect the ground

You use Trigger to synchronize the oscilloscope to your signal

Logic analyzer¶

Can sense microcontroller communication and display it digitally on your laptop.

salaea logic (software)

Can only see digital signals. No analog ones

Logic analysers can translate protocol to human readible stuffs

KiCad¶

PCB creation connect components and design circuits

Schematic¶

Create seperate schematics and connect them using labels.

Use labels to keep it clean.

alt text

If you press A you can see all components

alt text Now we search resistor and select it.

alt text

Now there is a resistor! Now we can also add a LED the same way.

alt text

Key	What?
W	Draw wire
A	New part
E	Edit value (Only works on components that can be edited)
X	Draw a trace
D	Drag Move something with traces
F	Finish the route for me

alt text Connector mounting pins

Make sure to add VCC and GND to your design even when you use pins to connect something

alt text Now we can go and make the circuit board.

Pcb layout part¶

In here you will define the physical placement of the pcb.

You can do anything with pcb's and you can make them any shape you want.

Assigning footprints¶

alt text When importing I got this error This is because we didn't tell KiCad what type of components they are (SMD or through pins)

Tools -> assign footprints

alt text After you've assigned it all it should look like this.

Custom shape¶

alt text On the right you see a lot of layers.

Silkscreen - Text Solder mask - Prevent solder to stick to that mask EdgeCuts - Shape of the pcb F.Cu - Front copper

Design rules¶

The closest track space can be the size of the tool (0.4mm) Always should give traces some more spaces between each other because otherwise its going to be super hard to check it with a multimeter.

File -> Board setup -> design rules

alt text In here yo can set design rules for the print. These settings are based on the machine it is produced on.

For high power circuits you need to set bigger traces otherwise you have a higher resistance and the traces will get hot.

alt text Don't forget to change the settings in Net Classes

Exporting the board¶

File -> Export ->

Via - Circle through pcb

everything comes from digikey