Electronic Components

What are the 2 types of transfomer?

What are the 2 types of transfomer?

what are the 2 characteristic of capacitor?

What are the meaning of forward bias and reverse bias?

what are the meaning of base emmiter and collector

How to test the transistor using VOM?

Melyssa120504* wrote:What are the different between capacitor and battery?

The potential energy in a capacitor is stored in an electric field, where a battery stores its potential energy in a chemical form and the battery is capable of storing more energy than capacitors. However, when a battery is discharging it can be slower than a capacitor ability to discharge because there is a latency associated with the chemical reaction to transfer the chemical energy into electrical energy.

Melyssa120504* wrote:What are the meaning of forward bias and reverse bias?

When voltage is applied across a diode in such a way that the diode allows current, the diode is said to be forward-biased while when voltage is applied across a diode in such a way that the diode prohibits current, the diode is said to be reverse-biased.

Melyssa120504* wrote:How to test the transistor using VOM?

You should follow these steps in testing a transistor:

Step 1: (Base to Emitter)

Hook the positive lead from the multimeter to the to the BASE (B) of the transistor. Hook the negative meter lead to the EMITTER (E) of the transistor. For an good NPN transistor, the meter should show a voltage drop between 0.45V and 0.9V. If you are testing PNP transistor, you should see “OL” (Over Limit).

Step 2: (Base to Collector)

Keep  the postitive lead on the BASE (B) and place the negative lead to the COLLECTOR (C).

For an good NPN transistor, the meter should show a voltage drop between 0.45V and 0.9V. If you are testing PNP transistor, you should see "OL" (Over Limit).

Step 3: (Emitter to Base)

Hook the positive lead from the multimeter to the to the EMITTER (E) of the transistor. Hook the negative meter lead to the BASE (B) of the transistor.

For an good NPN transistor, you should see “OL” (Over Limit).If you are testing PNP transistor, the meter should show a voltage drop between 0.45V and 0.9V.

Step 4: (Collector to Base)

Hook the positive lead from the multimeter to the to the COLLECTOR (C) of the transistor. Hook the negative meter lead to the BASE (B) of the transistor.

For an good NPN transistor, you should see “OL” (Over Limit).If you are testing PNP transistor, the meter should show a voltage drop between 0.45V and 0.9V.

Step 5: (Collector to Emitter)

Hook the postitive meter lead to the COLLECTOR (C) and the negative meter lead to the EMITTER (E) – A good NPN or PNP transistor will read "OL"/Over Limit on the meter. Swap the leads (Positive to Emitter and Negative to Collector) – Once again, a good NPN or PNP transistor should read “OL”.

If your bipolar transistor measures contrary to these steps, consider it to be bad.

You may also be able to use the voltage drop to determine which lead is the emitter on an unmarked transistor, as the emitter-base junction typically has a slightly higher voltage drop than the collector-base junction.

Remember: This test only verifies that the transistor is not shorted or open, it does not guarantee that the transistor is operating within its designed parameters. It should only be used to help decide if you need "replace" or "move on to the next component". This test works on bipolar transistors only – you need to use a different method for testing FETs.

What are the types of switches?

Melyssa120504* wrote:what are the meaning of base emmiter and collector

There are the three significant terminals of the transistor

Emitter: Emitter terminal is the heavily doped region as compared two base and collector. This is because the work of the emitter is to supply charge carrier to the collector via the base. The size of the emitter is more than base but less than the collector.
Base: The size of the base region is extremely small, it is less than emitter as well as the collector. The size of the base is always kept small so that charge carriers coming from the emitter and entering base will not recombine in the base region and will be directed towards the collector region. The doping intensity of base is also less than emitter and collector for the same reason mentioned above.
Collector: The collector terminal is moderately doped, and the size of the collector region is slightly more than emitter region because all the charge carriers coming from the emitter recombine at base and heat is released in this process. Thus, it is necessary for the collector terminal to be large enough so that it can dissipate the heat and the device may not burn out.

How do we identify the emitter, collector, and base of a transistor by using a multimeter? Which resistance is greater: base to emmitter or base to collector?

How Light Emitting Diodes Works ?

Light Emitting Diodes are almost everywhere. You can find LEDs in Cars, Bikes, Street Lights, Home Lighting, Office Lighting, Mobile Phones, Televisions and many more.

The reason for such wide range of implementation of LEDs is its advantages over traditional incandescent bulbs and the recent compact fluorescent lamps (CFL). Few advantages of LEDs over incandescent and CFL light sources are mentioned below:

Low Power Consumption
Small Size
Fast Switching
Physically Robust
Long Lasting

Because of these advantages, LEDs have become quite popular among a large set of people. Electronics Engineers, Electronic Hobbyists and Electronics Enthusiasts often work with LEDs for various projects.

What is the difference between a diode and an LED by the way ?

what are some types of LED's?

Integrated circuit (IC), also called microelectronic circuit, microchip, or chip, an assembly of electronic components, fabricated as a single unit, in which miniaturized active devices (e.g., transistors and diodes) and passive devices (e.g., capacitors and resistors) and their interconnections are built up on a thin substrate of semiconductor material (typically silicon). The resulting circuit is thus a small monolithic “chip,” which may be as small as a few square centimetres or only a few square millimetres. The individual circuit components are generally microscopic in size.

curteneyarellano wrote:what are some types of LED's?

Miniature LED’s
These are the one’s you see almost everyday in your life as indicators in mobile phones, television sets and a range of digital devices. They are usually available in market on a predefined,standard size & shape.
High Power LED
These LED’s are the result of advancements in semiconductor technology. As the name hints, these LED’s are known for its high output. They are capable of producing light output with higher luminous intensity. High power LED’s come in different shapes & sizes
Application Specific LED (AS-LED)
These are LED’s which are manufactured for a particular application in mind. Some examples are digital billboards, public displays, bi color & tri color LED’s.

What's the use of a relay in a circuit?

jine wrote:What is the difference between a diode and an LED by the way ?

A diode is a semiconductor device that essentially acts as a one-way switch for current. It allows current to flow easily in one direction.
Diodes have polarity, determined by an anode (positive lead) and cathode (negative lead).

A light-emitting diode (LED) is a semiconductor device that emits visible light when an electric current passes through it.
It also has polarity, the short leg is the negative lead and the long leg is the positive lead.

Melyssa120504* wrote:What are the 2 types of transfomer?

There are two types of transformers based on voltage levels.
These are the most commonly used transformer types for all the applications. Depends upon the voltage ratios from primary to secondary windings, the transformers are classified as step-up and step-down transformers.

Step-Up Transformer

As the name states that, the secondary voltage is stepped up with a ratio compared to primary voltage. This can be achieved by increasing the number of windings in the secondary than the primary windings as shown in the figure. In power plant, this transformer is used as connecting transformer of the generator to the grid.

Step-Down Transformer

It used to step down the voltage level from lower to higher level at secondary side as shown below so that it is called as a step-down transformer. The winding turns more on the primary side than the secondary side.

A slight background on LED's
The early years of the 1960s consisted of a 'race' in the field of semiconductors. Gallium arsenide and germanium were some of the first semiconductors uses before silicon became the preferred material in the industry. Engineers were experimenting with p/n junctions. These devices were being developed as diodes since they can pass current in one direction by not the other. GE, Bell Labs,Lincoln Labs, RCA research labs, and Texas Instruments worked to develop semiconductors for power control and laser technology.

It was in this race that the LED was 'discovered' in the Fall of 1961 by James R. Biard and Gary Pittman. Gary had been working in the related field of solar cells since 1958. In their efforts to try to make an X-band GaAs varactor diode they created tunnel diodes (which had been developed first at Esaki). They placed the tunnel diode on a GaAs substrate and discovered that there must be light production going on during forward bias operation. Using an infrared detector just brought in from Japan they tested it and discovered that the devices lit up brightly!

Soon after this others made discoveries in the field, however TI was the first to get a patent and sell the first LED for $130 each. The SNX-100 was the first LED sold (summer of 1962). The LEDs were first used with IBM computers to replace tungsten bulbs that controlled punch card readers (infrared light was sent through the holes, or blocked by the card). Today there is a myriad of applications for the LED.

jine wrote:What are the types of switches?

There are 4 types of switches:

1.SPST (Single Pole Single Throw)
The SPST is a basic ON/OFF switch, that is used to connect or break the connection between two terminals.

2.SPDT (Single Pole Double Throw)
The SPDT switch is a three terminal switch, one terminal is used as input and remaining two terminals are used as outputs. It joins a mutual terminal to one or the other of two terminals.

3.DPST (Double Pole, Single Throw)
The DPST switch consists of two poles that means it includes two identical switches located on side by side. This switch is operated by one single toggle, which means that two discrete circuits are controlled at a time through one push.

4.DPDT (Double Pole Double Throw)
This switch is equal to two SPDT switches, it means two separate circuits, connecting two inputs of each circuit to one of two outputs. The switch position controls the number of ways and from the two contacts each contact can be routed.

Melyssa120504* wrote:The insertion of the resistor on a circuit is in parallel or series?

It varies on what kind of a circuit you would like to put the resistor but whether it is in parallel or series circuit you can place a resistor.

curteneyarellano wrote:What's the use of a relay in a circuit?

A relay is an electromagnetic switch operated by a relatively small electric current that can turn on or off a much larger electric current.