4 Transistor 500mW FM Transmitter Circuit Diagram

4 Transistor 500mW FM Transmitter Circuit Diagram

As shown, the audio ascribe is a microphone, which uses 2 x 2N3904 as the microphone audio preamplifier. The audio/mic ascribe akin is adjustable by agency of a 5k preset / potentiometer.

The ambit uses a Colpitts oscillator for abundance generation, which is chargeless active and operates at the axiological abundance i.e. no circuitous abundance multiplication or control. The abundance affability basic of the ambit consists of 2 5pF (picoFarad) capacitors and a distinct 10uH (micro-Henry) inductor. These apparatus can be adapted if a change in abundance is appropriate - conceivably alike replaced with capricious capacitors (if youre up to the challenge).

An achievement RF amplifier takes the abundance produced by the Colpitts oscillator and amplifier to about about the 500mW (0.5 Watt) ambit - so this is the almost achievement ability of this FM transmitter. You are brash that back this transmitter operates at the axiological frequency, and because there is no achievement filter, there is acceptable to be some abundance alluvion and harmonics/spurious emissions.

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AT89C2051 microcontroller circuit

Real time controller AT89C2051

Real time controller is a device used to exercise control over household device continuously ongoing and scheduled. The series of Real Time Controllers with microcontroller AT89C2051 which dituls in this article is a tool that can do that serve targeted. The series of Real Time Controller with Microcontroller AT89C2051 Atmel AT89C2051 uses a data processor and controller as device installed. 

In the application directly devices requires a separate interface from a wide range of Real Time Controllers with this AT89C2051 microcontroller. When will connect the device with the AC power source to use interface optocoupler (MOC) or solid state relay. Devices that can be connected with the series of Real Time Controller with Microcontroller AT89C2051 include lights, water machines, fans, electronic gate. The series of Real Time Controllers with this AT89C2051 microcontroller to control a height of water level, controlling the flame lights the scheduled SCARA and censored.

Specifications Series Real Time Controller with AT89C2051 Microcontroller

The series of Real Time Controller with Microcontroller AT89C2051 uses a computer to perform serial communication settings via computer. The series of Real Time Controller with Microcontroller AT89C2051 has 6 units of output channels that can be independently controlled depending on the program induced in the tool. Output in the series of Real Time Controller with AT89C2051 microcontroller requires an interface to deal with equipment that will be in control.

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18W Amplifier Schematic Circuit

18W Amplifier Schematic Circuit Part List

P1_____________22K Log. Potentiometer (Dual-gang for stereo)

R1______________1K 1/4W Resistor
R2______________4K7 1/4W Resistor
R3____________100R 1/4W Resistor
R4______________4K7 1/4W Resistor
R5_____________82K 1/4W Resistor
R6_____________10R 1/2W Resistor
R7_______________R22 4W Resistor (wirewound)
R8______________1K 1/2W Trimmer Cermet (optional)

C1____________470nF 63V Polyester Capacitor
C2,C5_________100µF 3V Tantalum bead Capacitors
C3,C4_________470µF 25V Electrolytic Capacitors
C6____________100nF 63V Polyester Capacitor

D1___________1N4148 75V 150mA Diode

IC1________TLE2141C Low noise, high voltage, high slew-rate Op-amp
Q1____________BC182 50V 100mA NPN Transistor
Q2____________BC212 50V 100mA PNP Transistor
Q3___________TIP42A 60V 6A PNP Transistor
Q4___________TIP41A 60V 6A NPN Transistor

J1______________RCA audio input socket

Power supply parts:

R9______________2K2 1/4W Resistor

C7,C8________4700µF 25V Electrolytic Capacitors

D2_____________100V 4A Diode bridge
D3_____________5mm. Red LED

T1_____________220V Primary, 15 + 15V Secondary, 50VA Mains transformer

PL1____________Male Mains plug

SW1____________SPST Mains switch

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Speed Fan Control Circuit using IC CD4017B

Speed Fan Control Circuit using IC CD4017B Circuit

The simple abstraction activity is use IC CD4017 to ascendancy 4 relays which affix anniversary pole. IC CD4017B which is counter-cum-1kHz decoder and the arresting is disconnected into ten according intervals, Which can be programmed, via the distinct location, 10-mode.

According to the backward advertisement of the continuance of the acting period, the agnate achievement of the CD4017 inhibits adverse CD4017 (per pole of circling and diode D6), and fires the triac.

Here transistor T2 acts as a disciplinarian transistor. Pin by 4017, with aught at the achievement of the sensor for the about-face to 0(zero ascertain output) anniversary canyon through zero.

Remark. The accepted beachcomber forms of assertive positions of the rotary switch, as declared in EFY Lab are in the account 1.

The ambit is able to administer for a ambassador in the activity lighting equipment, hot air, oven singal Universal AC motor, heating, etc.

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FREQUENCY TO VOLTAGE CONVERTER CIRCUIT

A very simple and low cost frequency to voltage converter based on the TC9400 IC from Microchip is shown here. TC9400 can be either wired as a voltage to frequency converter or frequency to voltage converter and it requires minimum external components. The functional blocks inside the TC9400 includes integrator opamp, 3uS delay circuit, one shot circuit, charge discharge control circuit, divide by 2 network and necessary drivers. This circuit finds application in a range of electronic projects like frequency meters, tachometers, speedometers, FM demodulators etc.

Circuit Diagram

In the circuit shown above the TC9400 is wired as a F to V converter that operates from a single supply. The circuit generates an output voltage that is proportional to the input frequency. The input frequency is applied to the pin11 (non inverting input of the internal comparator). In order to trip the comparator the amplitude of the input frequency must be greater than +/-200mV.Below this level the circuit will not work at any situation.

Whenever the input signal to the pin 11 of IC1 crosses zero to the negative direction the output of the internal comparator goes low. The 3uS delay circuit enables the Cref charge/discharge circuit after 3uS and this connects the Cref to the reference voltage and this charges the integrating capacitor Cint a specific amount of voltage. In the single supply operation the reference voltage is the potential difference between pin 2 and 7 of the TC9400. Each time the input frequency wave form crosses zero towards positive direction, the output of the internal comparator goes high and this disables the Cref charge/discharge circuit which creates a short circuit across the Cref leads. The voltage across the integrating capacitor Cint is retained because the only discharge path available is the 1M resistor Rint which is a too high and the voltage across Cint is the output voltage. Resistor Rbiasis used to set the bias current of the IC.

The potential divider network comprising of R6 and R7 makes sure that the input threshold tracks the supply voltage always. The clamp circuit using diode D2 prevents the input from going far negative in order to turn on the internal comparator. In simple words this section of the circuit can be generally termed as a level shifter.

The TC9400 manufacturers claim that it can accept a signal of any frequency at its input. In the practical side, for the proper working of this circuit the positive half of the input signal must have at least 5uS pulse width and for the negative half it must be greater than or equal to 5uS.

For calibration adjust the offset adjust trimpot to obtain 0V at the output with no input frequency applied. If you have a function generator, set frequency input to 10KHz and make adjustments in the value of Cref to get around 2.5 to 3 volts at the output. This calibration is meant for a maximum input frequency of 10KHz.

Important points to remember

• The circuit can be assembled on a Perfect board or PCB.
• The circuit can be powered from anything between 10 to 15V DC.
• R3 can be used for adjusting the offset voltage.
• In the circuit the inverting input of the internal comparator is referenced to 6.2V by using D1. So the input signals amplitude must be between 4V and the supply voltage (V+).
• The output voltage is also referenced to 6.2V in this circuit.
• The output voltage and input frequency of the F to V converter is related using the equation V out = V ref x C ref x F in where V out is the output voltage and F in is the input frequency.
• TC9400 and TL071  must be mounted on holders.
  

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2N3904 Transistor datasheet Diagram Circuit Emitter Follower Circuit Diagram

The schematic shown below diagrams the emitter follower circuit using 2N3904, an NPN silicon bipolar junction transistor. In the circuit provided, input signal is applied to the base of the transistor, but the output is taken from the emitter.
Instead of using 2N3904 transistors, this emitter follower circuit uses such parameters: 40V collector to emitter voltage (Vce), 6V emitter to base voltage (Veb), 200mA collector current (Ic), 300mW power dissipation (Pmax), 300Mhz frequency where internal capacitances cause gain to be reduced to unity (fT), 10pF internal emitter-base capacitance (Ceb), and 3pF internal base-collector capacitance (Cbc). 

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150W LM12 based audio amplifier circuit with explanation

LM12 operational amplifier can output currents up to 10A. The LM12 in encapsulated in TO-3 with 4 pins, can support up to 800W and has enough internal protections to prevent slacks from over-currents or over-heating.
You can use LM12CL with 30 V maximum voltage or LM12C with 40V maximum.
The L1 coil has 40 turns 1mm copper, coiled over R4. If you use LM12CL it is recomended to have toroidal transformer 2 x 22V. The output must be between 7 and 12A. Filtering capacitors must have at least 20.000 uF.
LM12 must be mounted with screws on a big heatsink (=<1.5 C/W) and electric isolated form the heatsink

LM12 amplifier circuit diagram

LM12 amplifier PCB layout

More audio amplifier circuits…

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TDA2822 Integrated Amplifier Circuits General

General integrated amplifier circuit external components and need more larger heatsink. This paper presents a simple amplifier circuit, made easy. TDA2822 amplifier integrated circuits used in music players, portable DVD and other audio playback; power is not great but you can satisfy the requirements of the hearing, and the circuit is simple, good sound quality, wide voltage range of characteristics such as the amateur production Small amp better choice.

Circuit as shown in Figure 5-107.TDA2822M amp with an integrated circuit to a BTL, (the use of mono and stereo when two) external components only one resistance and two capacitors, with no heatsink, the playback results were satisfactory.
Selection and installation of components:
IC TDA2822M to 8 feet dual inline package, if available can not buy TDA2822 instead, TDA2822 and TDA2822M the same package, which difference is: TDA2822M from 3 V to 15 V can work, and the maximum operating voltage TDA2822 only 8V. TDA2822 must use the voltage dropped to 8 V below. Numerical informal request R1, 10 k generally choose the carbon film resistors. C1 choice of polyester 0.1 uF capacitor, C2 for 100 uF/16V the electrolytic capacitor.

Figure 5-108 its printed circuit board map.

As a simple circuit, the PCB can be engraved shovel role of the rule of law James Shuimo sandpaper or a small amount of water polishes kraft paper, water wash dry, apply a layer of rosin alcohol solution, stem directly after the solder components to the copper foil surface. Welding good after the inspection correct, then no access to speakers, connected to power, between the positive and negative output voltage should be less than 0.1 V. Connected to speakers, hand-touch input, the speaker should be given greater "Ong" sound. Then try to enter the sound signal. Circuit boards do not have to drilling,


Should be used Note: Because this amp for direct coupling, it can not be with DC input signal components. If a DC input signal components must be input in a series connection of around 4.7-10 uF capacitor separated, otherwise, they will have great DC current flow through speakers, so as fever burned. In practice, if 5-107 plans to conduct appropriate reforms are desirable effect.

To improve the circuit as shown in Figure 5-109.

In use found that the volume opened the largest TDA2822M fever when hot, can give TDA2822M produced a heatsink, generally shown in Figure 5-110. Heatsink can be thick lmm, long 38 mm, width of 25 mm made of aluminum plate. And in the heatsink on the reopening of 5-to 6-10 mm, width l mm the slot, then do along the dotted line into a hot film, "I" shape. When first installed heatsink on the release point in TDA2822M. Click 5-111 (a) use the thin Bangzha to bear. It should be noted that the TDA2822M the pin number written on the side of the heatsink, so as to avoid mistakes when welding. And heatsink, volume open only to the most warm, good cooling effect. This method can also be used for other small integrated circuit heat dissipation. Amp circuit caused by two Walkman stereo power continue, to promote two small speakers, good effect.

You can build on the stereo two-channel input circuit, the use of power when a small point, but has it.

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LA3161 based Preamplifier circuit with explanation

Preamplifiers are used to amplify low level signals such as those from mikes, tape heads before they are fed into power amplifiers. Power amplifiers are generally less sensitive. Frequency response also can be suitably trimmed and modified at preamp stage. LA 3161 is one of those widely used in tape decks and amplifiers as a stereo preamplifier.

Block Diagram is shown in Figure. LA 3161 has two low noise preamplifiers with good ripple rejection on chip catering to stereo applications. External part count is low and Single In line (SIL))(Figure 43) package makes mounting easy. Wltile the operating voltage is 9V, the IC can tolerate voltages up to 18V. Typical input resistance is WOK and output resistance is 10K with an open loop gain of78dB. Block diagram of the IC is given below. Input is given at Pin 1 and 8, output is taken at Pin 3 and 6, and negative Feedback is given at Pin 2 and 7. Power is at Pin 5 and Pin 4 is the ground terminal. There is an internal voltage regulator.

Ready made PCBs, even populated PCBs are available using this very useful IC. You can still build one, with a Veroboard provided proper care is taken about the ground returns. It simply means that one should not connect ground terminals of output and input at the same place. This will create serious oscillations and normal hobbyist will be left in the woods. Please read general instructions for working with amplifiers in the end.

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LM317T based Voltage Regulator with Pass Transistor circuit

Here is the circuit diagram for LM 317 T voltage regulator with pass transistor .

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Simple Voltmeter Circuit

his circuit provides a simple means to determine the voltage of a low-impedance voltage source. It works as follows. P1, which is a 1-W potentiometer, forms a voltage divider in combination with R1. The voltage at their junction is buffered by T1, and then passed to reference diode D1 via R3. D1 limits the voltage following the resistor to 2.5 V. An indicator stage consisting of T2, R4 and LED D2 is connected in parallel with D1. As long as the voltage is not limited by D1, the LED will not be fully illuminated. This is the basic operating principle of this measurement circuit.

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Bass Booster Circuit

Bass Boost is todays sound... whether its the driving, gut-vibration pulsation of disco, or the solid bass line of soft, hard, or laid-back rock. One way to get the modern bass-boost sound without running out and buying an all-new expensive piece of equipment is to use a Bass Booster between your guitar, electronic organ or what-have-you, and the instrument amplifier. A bass booster strips the highs from the instruments output signal and amplifies low frequencies, feeding on "all-bass" sound to the instrument amplifier. Naturally, the bigger the speaker used with the amp, the more powerful the bass: use 15-inchers with the Bass Booster and you can rattle the windows. Bass Booster is powered by an ordinary 9 volt transistor radio battery. It can be assembled on a small printed board or on a veroboard using point to point wiring. The booster connects between your instrument and its amplifier through two standard RCA Jacks.

Circuit diagram:

Parts:

P1 = 50K
P2 = 100K
R1 = 22K
R2 = 470K
R3 = 47K
R4 = 10K
R5 = 470R
R6 = 1K
Q1 = 2N2222
C1 = 2.2uF-25v
C2 = 100nF-63v
C31 = 00nF-63V
C4 = 3.3uF-25v
C5 = 470uF-25v
D1 = 5mm. Red Led
Q1 = 2N2222
B1 = 9v Battery
J1 = RCA Audio Input Socket
J2 = RCA Audio Output Socket
S1 = On-Off Switch

Using Bass Booster:

Connect your electronic guitar or other electronic instrument to input jack J1; Connect output jack J2 to your instruments amplifiers normally-used input. With power switch S1 off, key S2 so the instrument feeds directly to the instrument amplifier. With P2 set full counter-clockwise (Off), turn power switch S1 on, key S2 once, and advance P2 for the desired Bass Boost level. To cut back to natural sound just stomp down on S2 and key the Bass Booster out. Dont worry about leaving power switch S1 on for several hours of a gig. The circuit pulls less than 1mA from the battery, so battery will last many, many months.

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Voltage to pulse Duration Converter Circuit Diagram

This is a circuit of Voltage-to-Pulse Duration Converter. This circuit is used to convert voltage into pulse duration by combining a timer IC and an OP Amp. Accuracies to better than 1% can be obtained with this circuit (a), and the output signals (b) still retain the original frequency, independent of the input voltage. 

Voltage-to-pulse Duration Converter Circuit Diagram

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Two Transistors Wireless Microphone FM Transmitter Circuit Schematic Diagram

Two Transistors Wireless Microphone FM Transmitter Circuit Schematic DiagramPlease be warned if operating this circuit might violate the regulation of your country, because this FM transmitter circuit radiate strong radio frequency to the environment. This wireless microphone is very sensitive, pick up every sound in the 20m radius, and transmit the radio signal up to 2 kilometers in open air. Here is the schematic diagram of the circuit:

The first transistor (Q1) is the pre-amplifier for the microphone, and you can ommit this circuit if you don’t want to transmit the sound picked up by the mic, for example you can can connect your mp3 player directly to C1. The core of this FM transmitter circuit is Q2, a modified Collpits oscillator that the frequency is determined by L1, C4, C6, and the transistor’s internal base-emitter capacitance. The antenna use 1/16 wave length to compromize between the efficiency and the size. If you want the microphone to be less sensitive, you can replace the R1 by a higher resistor, try 10k or 22k, and this might overcome the feedback problem if you use this wireless microphone FM transmitter for a public address system.

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Rail Detect Voltage LED Circuit

At this time’s a clean low supply rail detection circuit to outlay peanuts and takes a short time ago 20 minutes before so to make it to. Its power consumption is quite low, so it may perhaps effortlessly be alive built into battery-powered policy. as a replacement for of using an op amp, the circuit is built around three low-cost transistors (Q1-Q3). Diodes D1-D3 form a 1.8V voltage reference (Vref) in favor of the emitter of Q1. If the voltage across the voltage screen formed by R1 and VR1 is fewer than this, Q1 turns on and provisions Q2 with center bias current.

This turns on Q3 into proportion to this bias current which at that time drives LED1. The brightness of the LED gives an indication of the severity of the low voltage condition. The brighter the LED, the minor the supply voltage. Trimpot VR1 is adjusted so with the aim of LED1 emphatically comes on by the side of the desired low-voltage thrust. The current consumption is typically fewer than 2mA as LED1 is sour. as a final point, the help exposed in lieu of RLED is right and proper for 6-12V process. For other voltages, RLED can take place calculated using the formula RLED = (Vcc - 1.8)/0.01 (this equates to a current of approaching 10mA).

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20 Watt Class A Power Amplifier Circuit

A single-ended Class-A amplifier is essentially one where there is only one active driven output device. The passive "load" may be a resistor, an inductor (or transformer) or - as in this amplifier - a current sink. Of the three basic options, the current sink offers the highest linearity for the lowest cost, so is the ideal choice.

Some esoteric (some might say idiosyncratic) designs use inductors or 1:1 transformers, but these are bulky and very expensive. Unless made to the utmost standards of construction, they will invariably have a negative effect on the sound quality, since the losses are frequency dependent and non-linear.

This amp uses the basic circuitry of the 60W power amp (see Index), but modified for true Class-A operation - it should be pretty nice! This amp has been built by several readers, and the reports I have received have been very positive.

With simulations, everything appears to be as expected, but although I have yet to actually build it and test it out thoroughly, no-one has had any problems so far. Using +/-20 Volt supplies - either conventional, regulated or using a capacitance multiplier, it should actually be capable of about 22 W before clipping, but expect to use a big heatsink - this amp will run hot.

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KA2107 Tone control electronic circuit project

A very simple tone control electronic circuit project can be designed using the KA2107 integrated circuit manufactured by Samsung Electronics . This tone control electronic circuit project is very simple requiring few external electronic parts . As you can see in circuit diagram the KA2107 tone control circuit project is designed for stereo application and it has some additional functions like volume control and balance control between channels . Adjusting the 10k potentiometers (bass and tremble) you will modify the high and low output signal frequency .

This electronic circuit project must be powered from a simple 12 volt Dc power supply circuit , but it works fine also with a 8 volt or 14 volt DC power circuit .

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I2C Bus Electrical Isolation Diagram Circuit

When the SDA (Serial DAta) lines on both the left and right lines are 1, the circuit is quiescent and optoisolators IC1 and IC2 are not actuated. When the SDA line at the left becomes 0, current flows through the LED in IC1 via R2. The SDA line at the right is then pulled low via D2 and IC1. Optoisolator IC2 does not transfer this 0 to the left, because the polarity of the LED in IC2 is the wrong way around for this level. This arrangement prevents the circuit holding itself in the 0 state for ever. As is seen, the circuit is symmetrical. So, when the SDA line at the right is 0, this is transferred to the left. The lower part of the diagram, intended for the SCL (Serial CLock) line, is identical to the upper part.

Electrical Isolation For I2C Bus Circuit Diagram

Resistors R1, R4, R5, and R8, are the usual 3.3 kΩ pull-up resistors that are obligatory in each I2C line. If these resistors are already present elsewhere in the system, they may be omitted here. The current drawn by the circuit is slightly larger than usual since the pull-up resistors are shunted by the LEDs in the optoisolators and their series resistors. Nevertheless, it remains within the norms laid down in the I2C specification

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3000W Stereo Power Amplifier Circuit

Circuit Power Amplifier has a power output of up to 1500W RMS power amplifier circuit is often used to power sound systems keperlun for outdor. In the final image can be seen a series of power amplifiers using 10 sets of power transistors for the ending.

This power amplifier circuit using a transistor amplifier from the front, signal splitter, driver and power amplifier. Current consumption required is quite large power amplifier that is 15-20 A 1500W power amplifier circuits for this. Supply voltage needed by the power of this amplifier is the optimal working order symmetrical 130VDC (130VDC-130VDC ground). 1500W amplifier circuit below is a picture series of mono, stereo if you want to make it necessary to make two copies of the circuit. For more details can be viewed directly image the following 1500W power amplifier circuit.

The series of High Power Amplifier 1500W With Transistor

Click Image to view larger

In the above series of power amplifer 1500W is equipped to control a DC Offset function to set the power amplifier is turned on at the moment and with no input signal then the output should be 0VDC. Then also equipped with a flow regulator to the power amplifier bias. Final part of this power amplifier requires adequate cooling to absorb the heat generated. Power amplifier is not equipped with a speaker protector, therefore it is necessary diapsang protector on the speaker output so that when the power amplifier is not the case turned on the beat to the speaker that can damage the speaker.

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Basic Principles of the LC resonance circuit

If so far you are still confused how the actual origin of the resonance between the capacitor and the inductor is in progress, then the simple circuit above will answer your confusion.

By understanding a simple electrical circuit above hopefully we will be able to understand the working principle of a series of more complicated and complex that uses the relationship as a series inductor and capacitors transmitter and receiver.

Note the picture above, when the switch SW1 is pressed and released back then obtained by the same signal as in the picture above signal. Initially when SW1 is connected to the voltage supply, the capacitor will make filling fast. Then when SW1 is released charge on the capacitor will be used by the inductor as the supply voltage. In accordance with the general nature of the inductor that the DC signal will be considered ordinary wire inductor such that current flowing quickly through the inductor and the charge on the capacitor decreases rapidly exhausted. Uniquely current that was flowing through the inductor and capacitor will fill the empty capacitor back through the other terminal (negative cycle). Charging kapasior place quickly, then inductor will burden the back so that emptying of cargo going back. That so happens repeatedly (resonance occurs between L and C) until the electrical charge had been used up by these two components in the form of power losses. Equations between regular wire inductor is the inductor with wire work as usual at the time of current flowing to him. Inductors But unlike ordinary wire when current flows to him and vice versa. So it will not happen short circuit if the inductor to get the supply voltage alternating current (AC). But in ordinary wire short circuit will still occur even if the voltage of alternating current.

From the above analysis we can conclude that the LC resonance occurs because one component part affected by the characteristics of other components. For frequencies generated depend on the value of L and C itself. The greater the value of both the frequency will be smaller and smaller the value of both the frequency value will be even greater.

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