FM Radio Circuits
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A simple USB FM transmitter that could be used to play audio files from an MP3 player or computer on a standard VHF FM radio by connecting it to an USB port. The circuit use no coils that have to be wound. This USB transmitter can be used to listen to your.... -
A basic UUS 65 73 MHz fm transmitter circuit schematic which can be used as UUS oscillator with no explanation 65 - 73 MHz transmitter ( oscillator ) c.... -
The most important part of this 88-108 transmitter is the Colpitts oscillator. C3,C4,C5,C6,CD1-CD2 ans L1 determine the transmission frequency. The RF Osci.... -
This mosfet fm transmitter circuit is designed to be used for aligning FM radio receivers. It has a microphone amplifier with automatic gain control. The FM modulation is a voltage oscillator and the final stage is built with MOSFETs. A lowpass filter at the.... -
Sometimes I can find a station and sometimes I can`t find any stations. Probably the main problem when tuning is, as soon as you move your hands or body, let go of the tuning cap or touch the 10k pot, whatever station you had on will either disappear or.... -
This 2 meter 144 MHz fox hunt transmitter is used in amateur competitions where a hidden transmitter is to be ""hunted"" using mostly homebrewed receivers an.... -
With this technique, an extra cable to power the fm antenna amplifier is unnecessary. The RF signal and the DC current supplying the amplifier use the cable simultaneously. Check another FM antenna booster circuit diagram. The RF signal is however prevented.... -
Perhaps this is one of the simplest and smallest FM radio receiver that can receive the FM stations available locally. Its simple design makes it ideal for.... -
Let`s construct a low-power FM transmitter using surface-mount devices (SMD) that will be received with a standard FM radio. Soldering surface mounted devi.... -
This is a 1 watt fm amplifier with a good design that can be used to amplify a rf signal in the 88 - 108 MHz band. It is very sensitive if you use good rf.... -
Maxim now has available a series of five integrated oscillator building blocks in the MAX260x series which cover the frequency range between 45 and 650 MHz. The MAX2606 covers the VHF band, although the frequency can only be varied by approximately ±3 MHz.... -
This simple fm radio receiver circuit consists of a regenerative rf stage, TR1, followed by a two of three-stage audio amplifier, TR2 to TR4. In some areas.... -
This sensitive FM radio tuner is the right circuit for hobbyists who want to build their own tuners instead of buying a ""plug-n-play"" finished product. The.... -
If you know some language of programming as C +, PASCAL, VISUAL BASIC, DELPHI etc you can write a program which will send in the parallel door (378 I) of PC a number from 0 until 255 checking thus the tendency of expense of simple D/A of converter (that it.... -
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.... -
Together with a good directional antenna this high performance two-stage antenna amplifier for the VHF FM broadcast band will enable you to capture far removed (DX) stations. Alternatively, it will drastically improve reception of FM signals you`ve come to.... -
This inexpensive FM radio receiver antenna booster uses the BF324 TO92 style pnp transistor in a grounded-base configuration. The circuit may be used as a.... -
This simple FM wireless microphone transmitter can transmit speech over a short range. It can be used as a simple cordless microphone. The circuit uses two.... -
This FM oscillator can be used for wireless audio, microphone and part-15 applications where stable frequency modulated oscillators is needed. Lt can be va.... -
The FM modulator circuit (frequency modulation) is built with a Motorola MC1648P oscillator. Two varactors, Motorola MV-209 are used to frequency modulate the oscillator. The 5000 © potentiometer is used to bias the varactors for the best linearity. The.... -
This 70MHz rf power amplifier circuit uses the SD1143 transistor which provides a gain of about 14dB in this design. It uses the fact that a 175MHz device.... -
This is a small but quite powerful FM transmitter having three RF stages incorporating an audio preamplifier for better modulation. t has an output power of 4 Watts and works off 12-18 VDC which makes it easily portable. It is the ideal project for the.... -
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, this transmitter can.... -
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.... -
Although only low power this circuit may be tuned to operate over the range 87-108MHz with a range of 20 or 30 metres. I have used a pair of BC548 transistors in this circuit. Although not strictly RF transistors, they still give good results. I have used an.... -
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.... -
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This simple transmitter operates from a 9V battery as shown above. I personally built this for a purpose. This is how it happened:- "members of my singing group find it difficult to handle a FM mic in Church. The choir sings in acapella form and the....
New Circuits
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This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of.... -
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is.... -
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to.... -
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This.... -
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the.... -
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,.... -
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the.... -
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power.... -
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
Popular Circuits
The circuit consists of 6 building blocks and the first is the inverter between pins 1 and 2....
The device is a dc switch that is normally on via the forward biasing of Ql via R3. Ql now clamps...
The bar graph - a series of LEDs in a line, such as you see on an audio display - is a common...
The schematics on this page are provided strictly for educational purposes. If anyone intends to...
A very simple and low cost frequency to voltage converter based on the TC9400 IC from Microchip...
This is the diagram of VHF RF Preamp circuit 100-175 MHz with single chip MAX2633. The circuit...
This switch will suit the Modular Burglar Alarm circuit. However, it also has other applications....
Building VFOs in 2011 might seem an irrelevant exercise given the move to and evolution of...
Circuit characteristic is the elimination of the external input resistors, thereby reducing the...