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Cara soldering

Soldering is the only permanent way to ‘fix’ components to a circuit. However, soldering requires a lot of practice as it is easy to ‘destroy’ many hours preparation and design work by poor soldering. If you follow the guidelines below you have a good chance of success.

1. Use a soldering iron in good condition. Inspect the tip to make sure that it is not past good operation. If it looks in bad condition it will not help you solder a good joint. The shape of the tip may vary from one soldering iron to the next but generally they should look clean and not burnt.

2. A PCB eraser is used to remove any film from the tracks. This must be done carefully because the film will prevent good soldering of the components to the PCB. The tracks can be checked using a magnifying glass. If there are gaps in the tracks, sometimes they can be repaired using wire but usually a new PCB has to be etched.

3. The heated soldering iron should then be placed in contact with the track and the component and allowed to heat them up. Once they are heated the solder can be applied. The solder should flow through and around the component and the track

4. Having completed soldering the circuit the extended legs on the components need to be trimmed using wire clippers. The circuit is now ready for testing.

kod warna resistor

Fungsi Breadboards

Breadboards are used to test circuits. Wires and components are simply pushed into the holes to form a completed circuit and power can be applied. One of the main advantages of using a breadboard is that the components are not soldered and if they are positioned incorrectly they can be moved easily to a new position on the board.
On the breadboard (diagram 1) seen opposite, letters are used to identify vertical columns and numbers to identify horizontal rows.











The red lines on diagram 2 show how some vertical columns and horizontal rows are internally connected. When power is applied to the breadboard current flows along these internal connections.

Diagram 3 shows how a 380 ohm resistor and an LED are setup on a breadboard. When a 9 volt battery is attached the LED lights. Try replacing the resistor with a higher value such as a 680 ohm resistor. The resistance will be greater and the LED should shine less bright.

Bulb

Bulbs have been used in electronics for along time and they are used in a wide range of circuits. Almost everyone has used a torch and if you look closely at the light source, it is more than likely that it is a bulb. In more recent years bulbs have been slowly replaced by LEDs as these are brighter, much more reliable, cheaper, energy efficient and have a much longer working life. They are also available in a range of colours. However, bulbs are still popular.

L.E.D

Light Emitting Diodes (LED) are very rugged, they last a very long time and they are an optical source. (A LIGHT SOURCE)
LEDs produce red, green, yellow, or orange light. They are used in a range of products

Infrared LEDs are also available although light from this type cannot be seen by the human eye. These are used in security devices.
LEDs are part of the diode family, consequently they must be connected the right way round or current will not pass through. They are usually protected by a resistor.

bateri sel kering

Batteries come in all shapes and sizes. They store electrical charge and as we all know when they are put into an electronic device such as a portable radio, they provide the power. The usual battery sizes are seen opposite. These are the type used in school projects and range from 1.5 volts to 9 volts.
School projects are powered by batteries because they are safe, easily bought and safe.

Pembahagian voltage

What are they - they can be used to split the voltage of a circuit. They are widely used in electronic circuits for setting and adjusting voltages - e.g. in radios, games and toys. You may find that you need a supply of 6 volts and you have a 9 volt battery, your only option may be to make a potential divider.

When two resistors of equal value (e.g. 1K) are connected across a supply, current will flow through them. If a meter is placed across the supply shown in the diagram it will register 9v. If the meter is then placed between the 0v and the middle of the two resistors it will read 4.5v. The battery voltage has been divided in half.

If the resistor values are changed to 2K and 1K the voltage will be 6v. The voltage at the centre is determined by the ratio of the two resistor values and is given by the formula:

V = supply voltage x R₂/R₁+R₂

_{V= 9v x 2000}

_1000+2000

v = 9v x (2000/3000 ohms)

V = 9v x 0.6666666 ohms

V = 6v

Fungsi capacitor dalam litar

USING A CAPACITOR AS PART OF A 555 TIMER

The 555 circuit shown above is more sophisticated than the circuit above and is composed of several components included the integrated circuit (NE555). When switched on the buzzer sounds for a certain amount of time.
Some of the components are resistors and capacitors. It is often the combination of resistors and capacitors that control the time delay - in this case the length the buzzer sounds for.
If the capacitor C1 is changed for a higher value capacitor then the buzzer sounds for a longer period of time. The variable resistor VR1 can also determine the length of time.

Capacitor

A capacitor (formerly known as condenser) is a device for storing electric charge. The forms of practical capacitors vary widely, but all contain at least two conductors separated by a non-conductor. Capacitors used as parts of electrical systems, for example, consist of metal foils separated by a layer of insulating film.

A capacitor is a passive electronic component consisting of a pair of conductors separated by a dielectric (insulator). When there is a potential difference (voltage) across the conductors, a static electric field develops across the dielectric, causing positive charge to collect on one plate and negative charge on the other plate. Energy is stored in the electrostatic field. An ideal capacitor is characterized by a single constant value, capacitance, measured in farads. This is the ratio of the electric charge on each conductor to the potential difference between them.

Capacitors are widely used in electronic circuits for blocking direct current while allowing alternating current to pass, in filter networks, for smoothing the output of power supplies, in the resonant circuits that tune radios to particular frequencies and for many other purposes.

Charge separation in a parallel-plate capacitor causes an internal electric field. A dielectric (orange)

reduces the field and increases the capacitance.

A capacitor consists of two conductors separated by a non-conductive region.^[8] The non-conductive region is called the dielectric or sometimes the dielectric medium. In simpler terms, the dielectric is just an electrical insulator. Examples of dielectric mediums are glass, air, paper, vacuum, and even a semiconductor depletion region chemically identical to the conductors. A capacitor is assumed to be self-contained and isolated, with no net electric charge and no influence from any external electric field. The conductors thus hold equal and opposite charges on their facing surfaces,^[9] and the dielectric develops an electric field. In SI units, a capacitance of one farad means that one coulomb of charge on each conductor causes a voltage of one volt across the device

Several capacitors in parallel.

Networks

For capacitors in parallel

Capacitors in a parallel configuration each have the same applied voltage. Their capacitances add up. Charge is apportioned among them by size. Using the schematic diagram to visualize parallel plates, it is apparent that each capacitor contributes to the total surface area.

For capacitors in series

Several capacitors in series.

Connected in series, the schematic diagram reveals that the separation distance, not the plate area, adds up. The capacitors each store instantaneous charge build-up equal to that of every other capacitor in the series. The total voltage difference from end to end is apportioned to each capacitor according to the inverse of its capacitance. The entire series acts as a capacitor smaller than any of its components.

Capacitors are combined in series to achieve a higher working voltage, for example for smoothing a high voltage power supply. The voltage ratings, which are based on plate separation, add up, if capacitance and leakage currents for each capacitor are identical. In such an application, on occasion series strings are connected in parallel, forming a matrix. The goal is to maximize the energy storage of the network without overloading any capacitor

SMD resistor

SMD resistors

Surface mounted resistors are printed with numerical values in a code related to that used on axial resistors. Standard-tolerance surface-mount technology (SMT) resistors are marked with a three-digit code, in which the first two digits are the first two significant digits of the value and the third digit is the power of ten (the number of zeroes). For example:

334	= 33 × 104 ohms = 330 kilohms
222	= 22 × 102 ohms = 2.2 kilohms
473	= 47 × 103 ohms = 47 kilohms
105	= 10 × 105 ohms = 1.0 megohm

Resistances less than 100 ohms are written: 100, 220, 470. The final zero represents ten to the power zero, which is 1. For example:

100	= 10 × 100 ohm = 10 ohms
220	= 22 × 100 ohm = 22 ohms

Sometimes these values are marked as 10 or 22 to prevent a mistake.

Resistances less than 10 ohms have 'R' to indicate the position of the decimal point (radix point). For example:

4R7	= 4.7 ohms
R300	= 0.30 ohms
0R22	= 0.22 ohms
0R01	= 0.01 ohms

Precision resistors are marked with a four-digit code, in which the first three digits are the significant figures and the fourth is the power of ten. For example:

1001	= 100 × 101 ohms = 1.00 kilohm
4992	= 499 × 102 ohms = 49.9 kilohm
1000	= 100 × 100 ohm = 100 ohms

000 and 0000 sometimes appear as values on surface-mount zero-ohm links, since these have (approximately) zero resistance.

More recent surface-mount resistors are too small, physically, to permit practical markings to be applied.

microfon

A microphone, sometimes referred to as a mike or mic, is an acoustic to electric transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, tape recorders, hearing aids, motion picture production, live and recorded audio engineering, in radio and television broadcasting and in computers for recording voice, VoIP. Several early inventors built primitive microphones prior to Alexander Bell, but the first commercially practical microphone was the carbon microphone conceived in October, 1876 by Thomas Edison.

Alat ukur

Voltage, current and resistance can easily be measured by using a multimeter. However, an ammeter measures current, a voltmeter measures the potential difference (voltage) between two points, and an ohmmeter measures resistance. However, a multimeter measures all these. There are two types, analogue and digital. The multimeter is the most important electronic test instrument. Two wires are normally used along with the multimeter (called probes) and they are colour coded - black and red.

A DIGITAL Multimeter is highly accurate and easier to read than an analogue type. It is best used for finding the precise value of a voltage, current or resistance.
An ANALOGUE Multimeter is less expensive and less precise than a digital type. Often it will be used for measuring a slowly changing voltage, current or resistance.

Relay

A relay is an electromagnetic switch. In other words it is activated when a current is applied to it. Normally a relay is used in a circuit as a type of switch (as you will see below). There are different types of relays and they operate at different voltages. When you build your circuit you need to consider the voltage that will trigger it.

EXAMPLE CIRCUIT

This simple circuit activates the relay only when the LDR is dark (covered). This could be used as part of an automatic animal feeder. For instance, if the animal was fed at night the circuit above would activate the relay. A second circuit, connected to the other side of the relay releases food into a dish.

Wirewound

Wirewound resistors are commonly made by winding a metal wire, usually nichrome, around a ceramic, plastic, or fiberglass core. The ends of the wire are soldered or welded to two caps or rings, attached to the ends of the core. The assembly is protected with a layer of paint, molded plastic, or an enamel coating baked at high temperature. Because of the very high surface temperature these resistors can withstand temperatures of up to +450 °C.^[5] Wire leads in low power wirewound resistors are usually between 0.6 and 0.8 mm in diameter and tinned for ease of soldering. For higher power wirewound resistors, either a ceramic outer case or an aluminum outer case on top of an insulating layer is used. The aluminum-cased types are designed to be attached to a heat sink to dissipate the heat; the rated power is dependent on being used with a suitable heat sink, e.g., a 50 W power rated resistor will overheat at a fraction of the power dissipation if not used with a heat sink. Large wirewound resistors may be rated for 1,000 watts or more.

Because wirewound resistors are coils they have more undesirable inductance than other types of resistor, although winding the wire in sections with alternately reversed direction can minimize inductance. Other techniques employ bifilar winding, or a flat thin former (to reduce cross-section area of the coil). For most demanding circuits resistors with Ayrton-Perry winding are used.

Applications of wirewound resistors are similar to those of composition resistors with the exception of the high frequency. The high frequency of wirewound resistors is substantially worse than that of a composition resistor