Basic Electronics2.pdf

8/13/2019 Basic Electronics2.pdf

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BASIC ELECTRONICSWorkpackage: Basic Electronics

Description: In this worksheet, you'll learn how to make use of basic electroniccomponents like a resistor or a LED. You will get in touch with someof fundamental laws of electronics. You will also meet the mostbasic electronic components used to create circuits in almost anyelectronic device.

Difficulty (1-10): 1

Overview: - Meet the fundamental concepts

- Discover which components are available- How to build a circuit- Troubleshooting- Useful Resources

Requirements: You should be able to read.


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handson.dmt.fh-joanneum.at

Carelse, Pauger, Pilz 2

FUNDAMENTAL CONCEPTS

Terms

Electrical CircuitAn electrical circuit, or also callednetwork, is a collection of electricalcomponents such as switches, resistors,capacitors and voltage sources. Thiscomponents are connected in a closedloop.

Voltage [V]Voltage, also known as electric potential, is the driving force in every electric circuit. Itrepresents the charge between two points. It is important to mention that there is no fixed pointof measurement, it is always measured as a reference. This means that the voltage ismeasured against the lower potential.

The following picture will help to describe this a little better:

You see a diagram with several different voltages.1. Starting at 8V the higher potential is point A. So compared to B, A is 3V bigger than B.

If you measure from B to A, you get 3V. If you measure from A to B, you will get -3V. Ifyou use Point A as the positive connector and point B as the ground connector, youcan power a circuit with 3V. Point B will be the referenced ground.

2. Starting at A you will encounter 6V is your ground is located at 0V. If you move yourground down to B, you will measure 8V. Again, if you would use A and B for poweringa circuit, your new referred ground would be at actual -2V. But for the circuit it wouldbe again, 0V.

3. Same like point 2, but this time the distribution is equal.


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Current [I]

The next important thing you will encounter in an electrical circuit is what is called current. Ingeneral all this electrical things are a bit hard to explain, but the current is a bit easier toexplain than the rest. You can compare it with your water tap. If you open the tap, water will

come out. Depending on the pressure and the diameter of the tap, more or less watermolecules are leaving the tap. This amount of molecules can be considered as the current,whereas the pressure is the voltage and the diameter of the tube is referred to as theresistor.

Resistance [R]

In every electrical circuit there is something what is called resistance. Resistance isnecessary to create a valid circuit. With just a small resistance value, or even worse, withouta resistance an electrical circuit becomes faulty. The current increases, the consumed powerof the circuit increases dramatically and creates heatmostly too much heat.

Almost every electrical component has its own resistance value. But there are some specialcomponents called resistors. Mostly this resistors are made of materials showing thebehavior of a bad electric conductor. This results in generating heat.

Power [W]

The electrical power is a value which you can calculate from your voltage and current values.If you buy electrical components, several different factors are importantpower is one ofthem. If you design your circuit without considering the maximum power components might

end up destroyed.

Electronic components

Resistors

As mentioned before, resistors are necessary for every electrical circuit.Almost any electrical component has its own resistance value. Even a

copper wire has its specific resistance value.

In almost any given circuit you will find resistors made of coal. Coal is amuch weaker conductor than copper with a higher specific resistancevalue. There are a lot of different resistors available, in Europe the socalled E6 family is very popular.

IMPORTANT: All the tiny, round resistors you will find for the workpackages justsupport 0.25 W only. Please make sure that your resistor consumes less or equal,otherwise it will be destroyed!


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The upper symbol is widely used in the US, in Europe the second symbol is usedmore commonly.

CapacitorsA capacitor is another electronic component. It is made out of thin foil

layers, which are separated from each other by a material which is notconducting. Between this layers electrical charges are stored.

Compared to a battery, a capacitor can store small capacities in arelatively small amount of time. There are two types of capacitors: anormal capacitor, and an electrolytic capacitor. There are two majordifferences between these two:

- The maximum capacity of an electrolytic capacitor is much higher- An electrolytic capacitor can be used just one-way. Like a diode it blocks in one

direction.Capacitors can be found in several use cases. The most popular are:

- Storing energy

- Compensating peaks in electronic signals by smoothing supply voltages

- Electronic filters

There are so much more components available, it is not purpose of this document todescribe and explain all these. Much more information is available on the internet.

DiodesA diode is a very commonly used electrical component with a very special behavior:

- A diode needs at least .7V to become a conductor

- A diode as a very low resistance in one direction, if the voltage is bigger 0.7V

- And a very high resistance in the other direction, which you can consider asblocked. At the voltage values we are working with, the diode is able to blockoncoming current completely. If you increase voltage over a specific limit, thediode will be destroyed.

Above you see two circuitsthe one on the left side is correct. The diode is in the correctposition and if the voltage at the diode is bigger than .7V, the circuit will work properly.

On the other hand, the second circuit is set up incorrectly. The diode will block the oncomingcurrent. Notice that our voltage supply just has a peak output of 3V, the diode will easilyblock this.

Free-running diode

The reason why diodes are mentioned is, that there is one very important use case: the free-running diode.


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Fundamental laws handson.dmt.fh-joanneum.at


When you control a stepper or servo motor with electronic components, these componentscan be destroyed if you dont use a free-running diode.

Fundamental laws

Fundamental LawsThe law of Ohm

IRU * [German]

RiV * [English]

Electrical power

IUP *

These two are the most fundamental laws you will be using through the differentworkpackages. With Ohmslaw you can calculate almost every normal resistor you will need,with the electrical power you can make sure that you wontkill the resistors in your circuit.

Useful Resources

http://www.electronics-tutorials.wsResistors

http://www.electronics-tutorials.ws/resistor/res_1.html

Capacitors

http://www.electronics-tutorials.ws/capacitor/cap_1.html

Diodes

http://www.electronics-tutorials.ws/diode/diode_1.html
http://www.electronics-tutorials.ws/http://www.electronics-tutorials.ws/resistor/res_1.htmlhttp://www.electronics-tutorials.ws/resistor/res_1.htmlhttp://www.electronics-tutorials.ws/capacitor/cap_1.htmlhttp://www.electronics-tutorials.ws/diode/diode_1.htmlhttp://www.electronics-tutorials.ws/diode/diode_1.htmlhttp://www.electronics-tutorials.ws/diode/diode_1.htmlhttp://www.electronics-tutorials.ws/capacitor/cap_1.htmlhttp://www.electronics-tutorials.ws/resistor/res_1.htmlhttp://www.electronics-tutorials.ws/

Documents

Basic Electronics2.pdf