Circuit-Zone.com - Electronic Projects
Posted on Sunday, April 3, 2016 • Category: FM Transmitters
This easy to build transmitter transmits high quality stereo sound from your MP3 player, computer, walkman or discman to any FM radio or car radio. The circuit is designed around the BA1404 single chip FM stereo transmitter from ROHM. The IC requires only a small number of external parts so it is well suited for hobbyist projects. The chip features excellent frequency stability, low power consumption & good channel separation. The transmitting RF frequency can be set by adjusting the coil (Lx). This 2 turn coils is paired with a 39 pF capacitor (Cx) to give a frequency range from 87 MHz - 106 MHz.
Posted on Sunday, March 20, 2016 • Category: FM Transmitters
This FM VHF transmitter will output approximately 250mW of RF power using a 2N3866 output transistor and can operate between 75MHz and 146MHz. It utilities a variable high gain audio pre-amplifier which can detect voices 40 feet away using an electret microphone. Using a NBFM scanner, ranges over 5KM have been achieved using a 48cm wire antenna. Coils are 22SWG 7mm air core. L1 and L2 should be 6 turns for 75MHz to 85MHz, 4 turns for 85MHz to 100MHz and 3 turns for 100 to 146MHz. For frequencies over 100MHz the Crystal will be higher than 20MHz hence the base emitter capacitor should be 47pF. L3 is a 4.7uH choke. It is ideal to tune up this circuit using a wave detector meter placed a few inches away from the transmitter.
Posted on Tuesday, February 23, 2016 • Category: FM Transmitters
Have you ever wanted to broadcast your own radio station within your neighborhood? This small and simple 87-108MHz FM transmitter is the toy that geeks have always wanted. This tutorial includes the PCB layout and the schematics. It has a range of up to 1/4 mile or more. It's great for room monitoring, baby listening and nature research.
Posted on Tuesday, February 16, 2016 • Category: Power Supplies
This is a high quality bench power supply with adjustable output voltage from 0 to 30V and adjustable output current from few miliamperes to 4 amperes. Built-in electronic output current limiter that effectively controls the output current makes this power supply indispensable in the experimenters laboratory as it is possible to limit the current to the typical maximum that a circuit under test may require, and power it up then, without any fear that it may be damaged if something goes wrong. There is also a visual indication that the current limiter is in operation so that you can see at a glance that your circuit is exceeding or not its preset limits.
Posted on Wednesday, February 3, 2016 • Category: FM Transmitters
FM transmitters can be complicated to build, but not this one ó this iPod FM transmitter about the easiest you can possibly make. And though the science of radio is well understood, thereís a magical, emotional quality about it that we donít often stop to appreciate. You will not forget the first time you pick up a transmission broadcast from a device you soldered together, yourself, from a few bits of copper, carbon, plastic, and wire.
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