If you want to be independent of the local radio stations for testing VHF receivers, you need a frequency-modulated oscillator that covers the range of 89.5 to 108 MHz ? but building such an oscillator using discrete components is not that easy. Maxim now has available a series of five integrated oscillator building blocks in the MAX260x series whic..
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Building your own ipod FM radio transmitter. It works quite easy, there is a power switch on the bottom to turn it on and tune your radio and transmitter to the right frequency. For the antenna you can use a copper wire of 70 cm. The range of this FM transmitter is about 100 to 150 meters (500 feet). With R5 you can adjus
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The FM transmitter circuit here works in the broadcast band 88 to 108MHz, and can be used to broadcast audio signals for remote listening. The output power..
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LM134 makes a good temperature sensor because it has a highly linear output characteristic. Because it is a current output device and is therefore not affected..
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Basically, this circuit is a radio frequency (RF) oscillator that operates around 100 MHz. The audio which is picked up and amplified by the electret..
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Current loop transmitter is the term associated with sensor system that is used in industrial 4-20mA current loop technology. This transmitter contain the..
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Bridged resistive sensing elements is common in resistive type sensors/transducers. This sensor type need a biasing voltage to operate. LM10 provide low..
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This AM radio circuit is a low power transmitter working on broadcast band. The simplicity is implemented using a single-transistor amplifier stage, and for..
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Create a rapid transmitter/receiver pair that anyone would have around their house. I decided that AM or FM radio would be good since everyone can receive that, and pondered how best to generate the necessary radio signal and modulate it appropriately. After a few LC oscillator designs, I thought about the RC oscillators built into most micro-controllers. I grabbed an ATMEL AVR I had on hand (an ATTiny44A)
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The picture to the left is a high quality radio transmitter for the A. M. broadcast band. The transmitter legally operates with "micro-power" and will not set any distance records but, unlike simpler designs, the frequency stays put and the fidelity is excellent. Although the schematic looks somewhat complex, the circuitry is easy to build and adju
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Free-running multivibrator keys power amplifier Q4 at audio role. Range is about 1 mile C6 tunes collector of oscillator to crystal frequency. -Texas lnstruments Inc. , "Transistor Circuit Design, " McGraw-Hill, N. Y. , 1963, p 361.
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Here is the single- 813 crystal oscillator transmitter, designed by RCA and exhibited in their advertisement on the back page of a "QST" magazine in 1938, and published by RCA in their HamTips bulletin, vol. 1, no. 4, dated December 1938. This transmitter`s output is 150 watts of CW or 100 watts of plate-modulated AM telephony. It seems obvious
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This is a variation of the the Electron Coupled Oscillator circuit, pioneered by Dow in 1931. Dow`s ECO has the screen "grounded" for RF. In this circuit, because I am using filament-type tubes instead of heater-cathode types, and because I didn`t want to build or use a pair of filament chokes with this first
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This circuit provides an FM modulated signal with an output power of around 500mW. The input Mic preamp is built around a couple of 2N3904 transistors, audio gain limited by the 5k preset. The oscillator is a colpitts stage, frequency of oscillation governed by the tank circuit made from two 5pF capacitors and the inductor. ( Click here for Colpit
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An AM voice transmitter with variable tuning. The antenna circuit is also tuned and transmits via a long wire antenna. Please Note. It is illegal to transmit on the AM wavebands in most countries, as such this circuit is shown for educational purposes only. Please read the disclaimer on this site before making any transmitter circuit. It is illega
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My site contains a few low power transmitters of one type or another, but until now no receiver. This circuit can be used to "sweep" an area or room and will indicate if a surveillance device is operative. The problem in making a suitable detector is to get its sensitivity just right; too much and it will respond to radio broadcasts, too little se
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This small transmitter uses a hartley type oscillator. Normally the capacitor in the tank circuit would connect at the base of the transistor, but at VHF the base emitter capacitance of the transistor acts as a short circuit, so in effect, it still is. The coil is four turns of 18swg wire wound around a quarter inch former. The aerial tap is about
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The power output of many transmitter circuits are very low because no power amplifier stages are incorporated. The transmitter circuit described here has an extra RF power amplifier stage, after the oscillator stage, to raise the power output to 200-250 milliwatts. With a good matching 50-ohm ground plane antenna or multi-element Yagi antenna, thi
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This is a small battery operated Tracking transmitter which broadcasts a repeating radio signal which can be detected by a directional antenna. The transmitter broadcasts an isotropic (radiates in all directions) signal on the FM band. An ordinary FM radio can be used to locate the transmitter, the reception of the signal will improve when the rad
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This is an Analogue TV Transmitter. Sound modulation is type FM with a 5. 5MHz carrier and video transmission is PAL. Frequency is adjustable via C5 and tunes 54 to 216Mhz with components shown. This is suitable for countries using TV systems B and G. Please Note: This circuit will be illegal to use in many countries, as such, it is displayed here
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Evolution FM transmitter with 2n2218 with audio amplification step using LM741 op amp with audio input for MP3, MP4, mobile, computer and other audio sources, beyond the traditional electret microphone. With great sensitivity to the input signal. Using fewer components and easy assembly makes it ideal for those who want even without much experienc
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This small circuit transmitter processes the signs of audio of a sound table or microphone, and the signs of video of a camera, or still the audio signs and video of a DVD, Video-cassette or even it sweats her video plate has an exit of composed video, you can transmit direct of your computer. Playing them in a channel free from the strip of VHF.
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This small transmitter can arrive the more than 1 km in favorable conditions of emission. The modulation can be made so much with a microphone, for an electrets microphone, or other audio source. The 5 turns of enameled thread 22 AWG, with diameter of 1 cm without nucleus. Look at the capacitors that it should be ceramic. The antenna should posses
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