CIRCUITS

(This entry is with educational purposes) In this entry, I will explain about circuits, starting from the basic things, like how to read a resistor, when two resistors are in parallel or in series, how to simplify a circuit, and other importants things that are importans, and the same time, basic, and easy to learn.

BASIC TERMS
Resistor: is the material that causes opposition to current flow.its measure is ohms
Voltage: is an electromotive force that pushes the electrons. its measure is volts
Electric current: is an orderly flow of electrons passing through a field. its measure is Amps.
DC voltage: Keeps the same value in the time
AC voltage: The voltage has a frequency and a period in a space of time
Period: Is the time that the sign delay in complete a cycle.
Frequency: Is the number of times that the sign repeats in a second.

HOW TO READ THE VALUE OF A RESISTOR? Next is the table of the values, depen of the band and of the color.

Parallel resistors: Two resistor are in parallel only when both are conected to a unique node, this node can have more ramfications. The resistor with the value of this parallel resistor you got with:the multiplication of both resistence, divide the sum of them. R(equivalent)=(R1*R2)/(R1+R2)

Series resistors: two resistors are in serie when they are connecte to diferents nodes, and this one doesn`t have more ramifications. the value of the final resistence is the sum of them. R(equivalent)=R1+R2

SIMPLIFICATION OF CIRCUITS

Next is a circuit, a simple one, let`s go to simplificate, and explain every step.
The value of the resistors: R1= 1k, R2= 2.2k, R3= 820, R4= 680, R5= 1.2k, R6= 560, R7= 470

Note 1: Each resistor is in ohms.

Note 2: when you got, k, you must multiplicate the coefficent per thousand.

Steps:


Simplification:



When we want know the values of the currents, and the voltage in each resistor, whe aplicate the ohm law: V/Rtotal=I

We got a voltage of 18volts.

and some others keys like:


Current Division law: Ix = (Rparallel1*Ienter)/(Rparallel1+Rparallel2)

The current in serie resistor are equal
Voltage Division Law: Vx=(Voltage*Rtoknow)/(Rtoknow+Rsieries)

the voltage in parallel resistor are equal

Value of currents:



Value of Voltages:

The value of the power that the resistence can stand you got with the final line in the last picture, where PRX=IRX*RX, is easy, and now the question is: What do we do with the power value?.

So, to answer the las question, let`s explain something: the resistors, actually you can buy they in an electronic store, normally the seller ask you if you want of 1, 0.5, 0.25 volts... then when you got the teoric value, you know that the resitor can stand the value of the power, if the value of the power is higher than the value of the resistor, this one ( the power in that resistor) will burn the resistor, so, in conclusion the value of the power the amount of power that falls in the resistance is dependent variant of the circuit.

Ok, so, now, let`s simulate, let`s check out that the values of the teoric simplification are true! I simulate with CIRCUIT MAKER 2000, I download a student version, from this website: http://rapidlibrary.com/index.php?q=circuit+maker+2000+download+rar. So, after the instalation of this software, let`s proced of this way. step by step:

1. open CIRCUIT MAKER 2000

2. from the left frame of this software, you can check out a list of multiple objects, multiple electronics complements

3. Open the list of the ticket "general", and then you choose the element tha you require, a resistor, a multimeter, a power, a source ground, etc.

4. the value of the resistor you can change: double click and choose or write the value that you need.

5.Finally, when the circuit is exactly equal to the circuit in this entry, you play it, or push F10, ah with the mouse, you put in power, current o voltage in each part of the circuit, you can check out.

NOTE: the value of the circuit can change in one or two tenths.

Next, I`ll put a screen picture, showing what are the things that you require in CIRCUIT MAKER 2000 ( in the red squares are some tics for the use of CIRCUIT MAKER 2000)



Note 1 : click in the picture show you with a best resolution a bigger than this actual screen shot!

Note 2: The last circuit are diferent to the circuit that we simplificate, and simulate, this one, are other example.

Now, to complete this entry, in a way more educational, more practical, a best way... we gonna check out some samples.

Samples of simplification

Sample 1: get the teoric, simulation way, and experimental results of the equivalent resistors.

That`s all for now. Thanks everyone!

Jorge Alberto Arroyave Manco

Ude@- Computer Sciencie

ITM- Electronic Design Engineering