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The C Shore

Introduction to Electronics

Table of Contents

Introduction to Electronics

Introduction

For the next section we will using some electronics, so let’s take a look at the parts we’ll be using and how we’ll connection them.

Power vs. Ground & Short Circuits

Ground

Ground is so-named because in power distribution it is achieved by connection a metal rod into the ground. Another name you may here is ‘neutral’ because it is at about the same level as a normal environment.

Power

Current (amount of electricity) flows from power to ground, and the higher the level of power(voltage), the more current that flows.

Short Circuits

If power is connected directly to ground it’s known as a short circuit because as much current as is possible will flow through the wire. This is usually a bad thing because it will generate large amounts of heat and ‘fry’ the connection.

Breadboard

Explain rows vs. columns, and the power traces.

Resistors

What a resistor is

A device the impedes the flow of electricity. This reduces current available to the rest of the circuit (V=IR). We use these to prevent too much current from flowing through an LED (LED have very little resistance which mean current through the LED can be very high if connected without resister because it’s essential a short circuit).

The more current flowing through a resister the great the amount of heat that is generated by the resistor’s dropping current. This is why a low resistance resister needs to be able to withstand higher temperatures than a high resistance resistor (since more current flows) through the low voltage resistor.

Resistor Colour Code

Colour bands were used because they were easily and cheaply printed on tiny components. However, there were drawbacks, especially for colour blind people. Overheating of a component or dirt accumulation may make it impossible to distinguish brown from red or orange. Advances in printing technology have now made printed numbers more practical on small components. The values of components in surface mount packages are marked with printed alphanumeric codes instead of a colour code.

To distinguish left from right there is a gap between the C and D bands.

Ring color Significant figures Multiplier Tolerance
None ±20
Pink ×10^−3 ×0.001
Silver ×10^−2 ×0.01 ±10
Gold ×10^−1 ×0.1 ±5
Black ×100 ×1
Brown 1 ×10 ±1
Red ×10^2 ×10 0 ±2
Orange ×10^3 ×1000 ±0.05
Yellow ×10^4 ×10000 ±0.02
Green ×10^5 ×100000 ±0.5
Blue ×10^6 ×1000000 ±0.25
Violet ×10^7 ×10000000 ±0.1
Grey ×10^8 ×100000000 ±0.01

LED

What it is

Light Emitting Diode — A diode only lets electricity through in one direction. For an LED, when electricity if flowing through the diode, it lights up.

Physical Characteristics (Oriention/Polarity)

  • Long leg opposite flat edge
  • Which way it’s connected (which side to power and which side to ground), matters.
  • The proper orientation is:

Raspberry Pi GPIOs

  • See next section.