Electronics

Now that You know the basic commands in Arduino there's one more thing that is necessary for You to master Arduino - electronics. This is the future. In this post You will learn the necessary information in therory and experience.

1. How does it work?

First, electricity is a synchronised movement of electrones from the negative pole to the positive pole. They have two po

les - positive and negative. When the circuit is closed, the electrones "travel" from the positive pole to the negative one. The poles are the electrodes in the batteries You connect the cables to. Example:

Warning! In some elements it is important to connect them correctly, which means: connect the positive pole of the element to the negative pole of the circuit. Also, don't connect the battery's two poles with a cable without adding elements. If You do so, it will be a short circuit that can produce much heat, destroy the battery, or when the battery is very strong (>9V), the cable can MELT,, BURN or even EXPLODE!

2. Semiconductors

They're mostly elements that take some energy to work, but decrease the circuit's power(V) by about 0.7 V. A good example is a well known LED diode.

First circuit!

Requirements:

* 3 L.E.D diodes

* 9V battery

* 2 cables

* a breadboard

Before You do it:

There are several rules You must follow to make a circuit.

1. What is a breadboard&how it looks and works:

You can see that the breadboad is divided into different segments. Below are the connections of the breadboard:

2. You must pin in the diode correctly. It's easy.

The diode has got two 'cables' coming out. The longer one is positive and the other one is negative. The + of the circuit has to be connected to the negative of the diode and the - of the circuit - to the longer cable of the diode. All the components that have one electrode longer follow the same rule.

A photo to make it easier:

3. Resistance. Don't burn Your L.E.D diode!

If You connect a L.E.D diode to a fully charged 9V battery, it will flash for half of a second, because the voltage (V) is to high and the diode will burn. In order to prevent it, use the resistor. Welcome, world!

The stripes on it show how much it will reduce the voltage. However, as it is not easy, we reccommend You to use the multimeter. Chose the measuring unit to Ohms (Omega sign) and experiment with different scales of measuring (e.x 1Ohm scale, 10Ohm scale, 100Ohm scale or 1kiloOhm scale). However, it is easier to download a resistor stripe resistance calculator.

Ohms, why Ohms?

GeorgeSimon Ohm has invented the Ohm's law speaking of resistance.

It tells that the voltage is amperage times resistance (U = I*R), so R=U/I and I = U/R

NOW, LET'S PROCEED TO THE CIRCUIT!

Photos:

One LED with a resistor shining at all its power.

Two led diodes connected shining at the same power, but each about twice weaker.

Three diodes didn't get enough power and aren't shining at all.

Why?

This is because of resistance. The diodes have been connected serially, which means one after another. In such situations the resistance becomes enormous and the LED diodes face more and more of it. If You want to make even 5 diodes flash as bright as they can, connect them parallelly, which means each diode is another 'mini circuit' - each diode is connected to the battery separatelly.

Photo:

3 diodes connected parallelly all shining the same and

with all their power. Unfortunatelly, the parallel connection

makes the battery go dead two times faster.

3. Capacitors

As, there was written in the post about components, capacitors, while being connected to the circuit, collect electricity until they're fully loaded. When You connect them serially, they will let electricity through only until they're not full. Connected parallelly or serially they discharge when You reverse thir poles.

The unit that measures a capacitor's capacity is Fahrads.

Most of the time, electrolytic capacitors (see in the post with electronical components) have got a 10uF to 5000uF, but the bigger ones can even have got up to 2000F and You will soon find out that even a thousand uF is a lot. The time of discharging depends on the capacity.

1000uF = 1000 microfahrads

This knowledge allows us to make another circut.

Requirements:

* Different capacity capacitors

* a L.E.D diode

* 9 V Battery

* 2 resistors

Our 9V battery has recently gone dead, so the circuit contains an accumulator and two strong resistors.

video 1:

What can we see here?

So, first, when I connect the capacitor to the circuit, the L.E.D diode will blink, because the capacitor loads quickly. Next, I reversed the poles and it discharged, so the L.E.D diode blinked again, because nnow the capacitor discarges.

As we alreadyknow, resistors modify the voltage a bit (see: Ohm's law), but mostly reduce the speed of the flow and amperage. That's why,if You place a very strong resistor or more than two resistors, the capacitor will discharge slower.

Video2:

Diodes!

But wait, we already know them! Yes, but in only 33%!

Ha! There are two types of diodes: Light-Emitting-Diodes and sillicon diodes.

Both of them have the same property, though - they can let electricity through only if their '-' is connected to the '+' of the circuit.

ZENER DIODES

When a diode is connected wrongly, we say it's connected prohibitively and does not conduct. If it's connected correctly, we say it's connection is conductive. However, zener diodes when connected prohibitively and the voltage is high, we say they are pierced - they conduct a bit of the high voltage in the prohibitive connection, but the rest, they don't let through.

Short circuit.

A Zener diode connected conductively:(9V battery is a bit old, so the voltage is a bit lower than 9V)

Prohibitive connection

See? The voltage now is only 0.7 V ! That' s because the Zener diode has got a very high voltage of a prohibitive state - it means that it lets some electricity through in the prohibitive connection only when the voltage is not less than 7.25 V - 0.7V = 6.55V (a math operathion based on the measurments). Different Zener diodes have got a different voltage of a prohibitive state.

Time for transistors!

These small pals have totally changed the whole electricity! Due to their size they can fit inside every circuit and there's no device that does not use them! What do they do? You can't count their functions - from a switch or logic gate up to an integrated circuit or a device that manipulates electricity in every way! As You can see that's a lot! You will need to learn much about them, though!

E - emiter - It powers collector. .For the electricity to come through it, the base must be connected to the circuit output(+)(e.g a L.E.D diode) and collectror must be connected to GND(-)

B - base - the main pin. There is most of the electricity. For electricity to come through the output of the circuit, both it and the emiter must be connected to the output or + of the circuit and the collector must be connected to GND(-)

C - collector. It powers emiter.For the electricity to come through it, the base must be connected to the circuit output(+)(e.g a L.E.D diode) and emiter must be connected to GND(-)

THIS IS ONLY ONE FACT ABOUT THE THREE PINS OF A TRANSISTOR. THERE ARE MANY, MANY MORE.

Circuit confirming the first property:

Schematic:

As we can see, the emiter hasbeen connected to GND. Electricity in it goes to the emiter that sends electricity to the L.E.D whereas the base always has to be connected, otherwise the transistor won't lead electricity through. Also, the base contains a silicon diode inside, so You can only connect it to + of the circuit. That's why, when we connect the GND to GND, the circuit stops working.

Difficult? Read this article a few times more and You shall understand it perfectly! That's how we did when we were having problems with understanding this property! Don't give up!

Second property:

Manipulating voltage

In this circuit, the transistor is in the saturation

state. It means that all the voltage is split everywhere - saying shortly. Then., the collector's voltage is only about 0.2V and the base - emiter voltage is 0.7 V, because most of it stays in the base or in the circuit's output. However, the output voltage is 2V(reduced by a resistor). The rest is in the inside of the transistor.

Here, the circuit lets us exactly see what happens inside a transistor.

The "+" of the circuit is connected to the base. The L.E.D diode is connected to the collector or emiter. The diode is flashing, because the base is powering the emiter(or collector). The orange cable is pinned to the emiter. If You connect it to the base, the diode will flash a bit brighter, because the current from the pin of the orange cable (which has been prieviously taken away from the base and collector) comes to the diode. However, if You connect the second ending of the orange cable to the pin of the L.E.D that is connected to the GND, the diode will stop flashing. That's because all the current from the base and the third pin(not the base and not the one from the orange cable) will go through the orange cable to its pin. The long the cable will be held to the L.E.D, the long You will have to wait for the L.E.D to brighten. That's because the current stores in the orange canble and its pin.

#arduino #breadboard