A light-dependent resistor is also a variable resistor but is controlled by the light versus turning a knob. The resistance in the circuit changes with the intensity of the light.
These are often found in exterior lights that automatically turn on at dusk and off at dawn. Capacitors store electricity and then discharges it back into the circuit when there is a drop in voltage. A capacitor is like a rechargeable battery and can be charged and then discharged. A diode allows electricity to flow in one direction and blocks it from flowing the opposite way. A light-emitting diode is like a standard diode in the fact that electrical current only flows in one direction.
The main difference is an LED will emit light when electricity flows through it. Inside an LED there is an anode and cathode.
The longer leg of the LED is the positive anode side. Transistor are tiny switches that turn a current on or off when triggered by an electric signal. In addition to being a switch, it can also be used to amplify electronic signals.
A transistor is similar to a relay except with no moving parts. A relay is an electrically operated switch that opens or closes when power is applied. Inside a relay is an electromagnet which controls a mechanical switch. This circuit contains electronic components like resistors and capacitors but on a much smaller scale. Integrated circuits come in different variations such as timers, voltage regulators, microcontrollers and many more. Before you design an electronic project, you need to know what a circuit is and how to create one properly.
An electronic circuit is a circular path of conductors by which electric current can flow. A closed circuit is like a circle because it starts and ends at the same point forming a complete loop.
In contrast, if there is any break in the flow of electricity, this is known as an open circuit. All circuits need to have three basic elements. These elements are a voltage source, conductive path and a load.
The voltage source, such as a battery, is needed in order to cause the current to flow through the circuit. In addition, there needs to be a conductive path that provides a route for the electricity to flow. Finally, a proper circuit needs a load that consumes the power. The load in the above circuit is the light bulb. When working with circuits, you will often find something called a schematic diagram.
These symbols are graphic representations of the actual electronic components. Below is an example of a schematic that depicts an LED circuit that is controlled by a switch. It contains symbols for an LED, resistor, battery and a switch. By following a schematic diagram, you are able to know which components to use and where to put them. These schematics are extremely helpful for beginners when first learning circuits. There are many types of electronic symbols and they vary slightly between countries.
Below are a few of the most commonly used electronic symbols in the US. To find the resistor value, you need to know the voltage and the amps for your LED and battery. Next, you need to find out what voltage your battery is.
In this example, we will be using a 9V battery. This will give you a voltage of 7 which needs to be divided by. Good day to you, I am trying to repair a PCB but am finding it difficult to procure the resistor that has blown. The resistor has specific coloured bands on it. Any suggestions on how to identify the manufacturer of this specific resistor?
I really hands off you not for the simple and easy explanation of the components of the but for the labour you did for finding all these informations in a simple way…….. Thank you very much………. You did a really good job explaining the parts of a circuit. Your explanation is much better for a beginner and I feel like the books would have made much more sense if I had read this first.
I ravi Kant like learning circit digram but I have no book and no institution and no teacher related this subject. Very good article for new electronics repairers,I am the new electronics repairman,I need to learn about ic can you help me? Thanks man. Really helped me for my science olympiad. I am 10 and will turn 11 on may 9th Normally i purchase leds from led I have made some DIYs before and last time it was a speaker with the led light.
You should try more, it was not very difficult as long as you have the right introduction and all tools on hand. Thank u so much for sharing great information with us. This info definately improve my knowledge about electronics…thanks. Thanks very much My teacher do not explain it well, But you let me understand it very well Thanks for help. Thank you for typing this up. I am trying to build a robot like baymax from Big Hero 6 by hand and looking up things used in computers, microchips, and codes that will help me in this case.
I am willing to make it learn two languages and to do things like this, I need to know the basics and this article helps me understand what I need and how to use it. This is some really good information about circuit boards. I liked that you pointed out that LEDs can be a really great visual feedback. It is good to know that a can help you figure out if it is working properly. Dear, i am confused about what you have written about resistor.
I think when we connect a resistor in series with the led the current will remain same because in series current remain same but voltage divides so i think in this case the resistor act as a voltage limiting resistor.
A LED without the resistor in series will have a lot of current flowing through it. But if you add a Ohm resistor in series with it, the current is 21mA. Thanks so much for this. Awesome software and community! Hey now, I have a box fan that stopped working. I tore it apart and found 1 electronic component, Besides the copper wire and the metal it was wrapped around. The component looks like a black box with a couple wires coming out of it.
Can you tell me what this little black box is and what it does in relation to the workings of the fan? Could you help me understand what these boxes are all about?
Whats up with that? By the way,your site is my goto electronics site when im confused. It helps me understand what the parts are and what they do, but my brain is confused when i look at all the parts, and i seem to instantly forget what they do, maybe some electric field fried my brain,but most likely…..
Sincerely, skin. Great article, i have read all your articles. I am working at allchips limited from last month, i want learn more. Our website is electronic components supply chain, but no explain of them…. Very good and easy description……. This is a great blog site for electronics hoviets, about the components used under the basics electronics and electronics sector, have been explained in detail in detail in this blag series, which is quite beneficial for those interested in electronics.
The way you explain flees my fears about electronics and inspires my passion to learn even more until I overflow with knowledge to share with technological knowledge based LOVE. Such an interactive tutorial. Thank you so much for putting in your thoughts.
I am sure it will help many. Great work :. Excellent overview of basic electronics components such as capacitors, transistors, Leds and resistors. I worked with high frequency electronics in the defense industry until I became disabled with Lupus. Ohmify will help me teach some really cool stuff to my grandkids. But, if you introduce a resistor in the circuit, it will reduce the flow of current to an optimal level. Thus, you can keep the LED on longer without overheating it. Resistors are also used to reduce the voltage to the desired level.
Sometimes, a particular part of a circuit such as a microcontroller may need a lower voltage than the circuit itself. This is where a resistor comes in. However, the microcontroller needs only a 6V supply. So, to divide the voltage in half, all you have to do is place two resistors of equal resistance value in series.
The wire in between the two resistors will have halved the voltage of your circuit where the microcontroller can be attached. Using appropriate resistors, you can lower the voltage within the circuit to any level. Resistors are also used in combination with capacitors to build ICs that contain resistor-capacitor arrays in a single chip.
They are also known as RC filters or RC networks. They are also used in machine tools, switchgears, motor controllers, automated equipment, industrial appliances, elevators, and escalators. A diode is a two-terminal device that allows electric current to flow in only one direction.
Thus, it is the electronic equivalent of a check valve or a one-way street. It is made either of a semiconductor material semiconductor diode or vacuum tube vacuum tube diode. Today, however, most diodes are made from semiconductor material, particularly silicon. As mentioned earlier, there are two types of diodes: vacuum diodes and semiconductor diodes. A vacuum diode consists of two electrodes cathode and anode placed inside a sealed vacuum glass tube.
A semiconductor diode comprises p-type and n-type semiconductors. It is, therefore, known as a p-n junction diode. It is usually made of silicon, but you can also use germanium or selenium.
When the cathode is heated by a filament, an invisible cloud of electrons, called space charge, forms in the vacuum. Though electrons are emitted from the cathode, the negative space charge repels them. However, when the anode is made positive, the space charge vanishes. As a result, current starts flowing from the cathode to the anode. Thus, electric current within the diode flows only from the cathode to the anode and never from the anode to the cathode.
A p-n junction diode comprises p-type and n-type semiconductors of silicon. The p-type semiconductor is usually doped with boron, leaving holes positive charge in it. The n-type semiconductor, on the other hand, is doped with antimony, adding a few extra electrons negative charge in it.
So, electric current can flow through both semiconductors. When you put p-type and n-type blocks together, the extra electrons from the n-type combine with the holes in the p-type, creating a depletion zone without any free electrons or holes. In short, current can no longer pass through the diode. However, if you reverse the terminals reverse-bias , no current flows through the diode because holes and electrons are pushed away from each other, widening the depletion zone.
So, just like a vacuum diode, a junction diode can also allow current to pass in one direction only. Though diodes are one of the simplest components in an electronic circuit, they have unique applications across industries. The most common and important application of a diode is the rectification of AC power to DC power. Usually, a half-wave single diode or a full-wave four diodes rectifier is used to convert AC power into DC power, particularly in household power supply.
When you pass AC power supply through a diode, only half the AC waveform passes through it. As this voltage pulse is used to charge the capacitor, it produces steady and continuous DC currents without any ripples. Different combinations of diodes and capacitors are also used to build various types of voltage multipliers to multiply a small AC voltage into high DC outputs.
Bypass diodes are often used to protect solar panels. When the current from the rest of the cells passes through a damaged or dusty solar cell, it causes overheating.
As a result, the overall output power decreases, creating hot spots. The diodes are connected parallel to the solar cells to protect them against this overheating problem.
This simple arrangement limits the voltage across the bad solar cell while allowing the current to pass through undamaged cells to the external circuit. When the power supply is suddenly interrupted, it produces a high voltage in most inductive loads. This unexpected voltage spike can damage the loads. However, you can protect expensive equipment by connecting a diode across the inductive loads. Depending on the type of security, these diodes are known by many names including snubber diode, flyback diode, suppression diode, and freewheeling diode, among others.
They are also used in the process of signal modulation because diodes can remove the negative element of an AC signal efficiently. The diode rectifies the carrier wave, turning it into DC. The audio signal is retrieved from the carrier wave, a process called audio-frequency modulation.
You can hear the audio after some filtering and amplification. Hence, diodes are commonly found in radios to extract the signal from the carrier wave. Reversing polarities of a DC supply or incorrectly connecting the battery can cause a substantial current to flow through a circuit.
Such a reverse connection can damage the connected load. The diode becomes forward-biased in the case of correct polarity and the current flows through the circuit. However, in the event of a wrong connection, it becomes reverse-biased, blocking the current. Thus, it can protect your equipment from potential damage.
One of the most crucial components of an electronic circuit, transistors have revolutionized the field of electronics. These tiny semiconductor devices with three terminals have been around for more than five decades now. They are often used as amplifiers and switching devices. In the beginning, Germanium was used to build transistors which were extremely temperature-sensitive. Today, however, they are made from Silicon, a semiconductor material found in the sand because Silicon transistors are much more temperature-tolerant and cheaper to manufacture.
Each transistor has three pins called Base b , collector c , and emitter e. When you sandwich a p-type silicon slab between two n-type bars, you get an NPN transistor.
The emitter is attached to one n-type, while the collector is attached to the other. The base is attached to the p-type. The surplus holes in the p-type silicon act as barriers, blocking the flow of the current.
However, if you apply a positive voltage to the base and the collector and negatively charge the emitter, electrons start flowing from the emitter to the collector. The arrangement and number of p-type and n-type blocks remain inverted in a PNP transistor. In this type of transistor, one n-type is sandwiched between two p-type blocks. As voltage allocation is different, a PNP transistor works differently. In short, the current must flow away from the base to turn a PNP transistor on.
Transistors function as both, switches and amplifiers in most electronic circuits. Designers often use a transistor as a switch because unlike a simple switch, it can turn a small current into a much larger one.
Though you can use a simple switch in an ordinary circuit, an advanced circuit may need varying amounts of currents at different stages. One of the most well-known applications of transistors is the hearing aid. Usually, a small microphone in the hearing aid picks up the sound waves, converting them into fluctuating electrical pulses or currents. When these currents pass through a transistor, they are amplified.
The amplified pulses then pass through a speaker, converting them into sound waves once again. Thus, you can hear a substantially louder version of the surrounding noise. Transistors are often hooked up with logic gates to build a unique piece of an arrangement called a flip-flop. It now flips on or off whenever new current passes through it. It is named after its inventor Sidney Darlington.
The sole purpose of a Darlington transistor is to deliver a high current gain from a low base current.
You can find these transistors in instruments that require a high current gain at a low frequency such as power regulators, display drivers, motor controllers, light and touch sensors, alarm systems, and audio amplifiers.
The Insulated-Gate Bipolar Transistor IGBT transistors are often used as amplifiers and switches in various instruments including electric cars, trains, refrigerators, air-conditioners, and even stereo systems. An inductor , also known as a reactor, is a passive component of a circuit having two terminals. This device stores energy in its magnetic field, returning it to the circuit whenever required. It was discovered that when two inductors are placed side by side without touching, the magnetic field created by the first inductor affects the second inductor.
It was a crucial breakthrough that led to the invention of the first transformers. It is probably the simplest component, comprising just a coil of copper wire. The inductance is directly proportional to the number of turns in the coil. Sometimes, however, the coil is wound around a ferromagnetic material such as iron, laminated iron, and powdered iron to increase the inductance. The shape of this core can also increase the inductance. Toroidal donut-shaped cores provide better inductance compared to solenoidal rod-shaped cores for the same number of turns.
Unfortunately, it is difficult to join inductors in an integrated circuit, so they are usually replaced by resistors. Whenever the current passes through a wire, it creates a magnetic field. However, the unique shape of the inductor leads to the creation of a much stronger magnetic field. This powerful magnetic field, in turn, resists alternating current, but it lets direct current flow through it. This magnetic field also stores energy. Take a simple circuit comprising a battery, a switch, and a bulb.
The bulb will glow brightly the moment you turn the switch on. Add an inductor to this circuit. As soon you turn the switch on, the bulb changes from bright to dim. On the other hand, when the switch is turned off, it becomes very bright, just for a fraction of a second before turning off completely.
As you turn the switch on, the inductor starts using the electricity to create a magnetic field, temporarily blocking the current flow. But, only DC current passes through the inductor as soon as the magnetic field is complete. All this time, the inductor stores some electrical energy in the form of magnetic field.
So, when you turn the switch off, the magnetic field keeps the current in the coil steady. Thus, the bulb burns brightly for a while before turning off.
Though inductors are useful, it is difficult to incorporate them into electronic circuits due to their size. As they are bulkier compared to other components, they add a lot of weight and occupy plenty of space.
Hence they are usually replaced by resistors in integrated circuits ICs. Still, inductors have a wide range of industrial applications. One of the most common applications of inductors is to select the desired frequency in tuned circuits. They are used extensively with capacitors and resistors, either in parallel or series, to create filters.
The impedance of an inductor increases as the frequency of signal increases. Thus, a stand-alone inductor can only act as a low-pass filter.
However, when you combine it with a capacitor, you can create a notched filter because the impedance of a capacitor decreases as the frequency of signal increase. So, you can use different combinations of capacitors, inductors, and resistors to create various types of filters. They are found in most electronics including televisions, desktop computers, and radios.
If an alternate current flows through an inductor, it creates an opposite current flow. Thus, it can convert an AC supply into a DC. A ferrite bead or ferrite choke is used to suppress high-frequency noise in electronic circuits. Some of the common uses of ferrite beads include computer cables, television cables, and mobile charge cables.
These cables can, sometimes, act as antennas, interloping with audio and video output of your television and computer. So, inductors are used in ferrite beads to reduce such radio frequency interference. Most proximity sensors work on the principle of inductance. An inductive proximity sensor comprises four parts including an inductor or coil, an oscillator, a detection circuit and an output circuit. The oscillator generates a fluctuating magnetic field.
The detection circuit determines the strength of the sensor, while output circuit triggers the appropriate response. Inductive proximity sensors, also called contactless sensors, are cherished for their reliability.
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