viernes, 2 de marzo de 2012

Series and parallel capacitors

Capacitors are one of the standard components in electronic circuits, and can be connected in series or in parallel.

  • Series capacitors: capacitors connected in series will have a lower total capacitance than any single one in the circuit, and is calculated as:

Let's do an example:  
What is the total capacity in this series capacitor?                     

We only have to do the formula, so:
C1= 3µF
C2= 7µF
C3= 23µF

Ctotal= 1/(1/3+1/7+1/23)= 1,92 µF
Remember!: µ means 10-6 (millionth), so 1000000µF = 1F

  • The formula for calculating the parallel total capacitance is the same form as for calculating series resistances: 
                                                     





Resistors, color code

Resistors are a little electrical components used to distribute properly the voltages and currents flowing through the circuit.
Resistors have some color code, which I will you explain what mean each:
As the picture show, there's a resistor of 4 bands in which there are 4 color code, that means:
-First band: is the first number of the value of the resistence.
-Second band: is the second number of the value of the resistence.
-Third band: represents the number of zeros to be added.
-Fourth band: is the tolerance value of the resistor.

In this table, you can see the value of the color code in a resistor:

In the case of the resistor showed before, will see how to now the resistance value.
The resistor has a brown, red, orange and gold band. This value resistence will be 12000 ohms with 5% tolerance. According to the table, brown color reperesents the "1", the red "2" and orange means that it adds three zeros.

Series and parallel circuits

There are two types of circuits, in series and in parallel:
  • In series:

In a series circuit the current is the same in every component, which can be easily measured or calculated. 
The total resistance is the sum of all resistances in the circuit.

  • In parallel:

 In a parallel circuit, the voltage across each component is the same, and the current through each component depends on its resistance.



Ohm's Law.

Ohm's Law defines the relationships between power (P), voltage (E), current (I) and resistance (R), which is measured in ohms. This law is defined as V= I·R and explains how to calculate the current:


In this example, there are 20V and 2000 ohm in the resistors in series. The current it's calculate like the 20V devided by the resistence, (1000 kiloohms in one, and 2000 kiloohms in other). So the current is 0,0066 Amperes.

The current can be measured also by the multimeter, mentioned above.
                                                 


Build a circuit and measure the voltage

First of all, to have to build a circuit, we need some electrical components that we will need to do it.
For it, we need a stripboard (1), where we set the resistors, and the multimeter, using crocodile clips (2) to connect it.






When we have built our circuit, we have to connect the resistors to the current, using the crocodile clips. Then we adjust the multimeter and place the clips into the resistors. With the  manual adjustment  roulette function , select a range greater than it will be measured (for example 40 V), it will be displayed in the lower right corner of the display. Doing this, the display will show the legend "DC", "V" and the range chosen, in this case "40". It can be showed at the screen the sign (-), that means that the clips were connected in reverse.
This is the first step.



How to analyze a circuit

Hi, my name is Ivan, and I am a student of aerospace engineering. I will you explain basically how to analyze a circuit corresponding to the subject of Navigation Systems I.
I hope you like my explanation!