AM receiver circuit using MK484

MK484 AM receiver circuit  Description. A simple AM receiver circuit based on the MK484 AM receiver IC from Rapid Electronics Ltd is shown here. MK4844 is a monolithic integrated circuit that has all the necessary sections of a AM receiver like RF amplifier, detector, AGC etc. The IC is available in TO92 package and requires very few external components. In the circuit L1 and C1 forms a tank circuit. L1 also serves as the antenna coil. The audio signals available at the pin 3 of IC1 are amplified using the amplifier built around transistor Q1. C2 is a bypass capacitor…

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Simplest FM Transmitter.

Description. Here is the circuit diagram of the simplest FM transmitter using a transistor. Great performance or range is not guaranteed here, because this is an elementary design. General purpose radio frequency transistor BF 494 (Q1) is used here for obtaining FM modulation. A condenser mic is used here to pickup the sound. The condenser mic converts the sound to electrical variations and this variations are fed to the base of Q1, which performs the amplification as well as modulation. The capacitor  C2  and L1 determines the frequency of transmission. The circuit can be powered from a 9V transistor radio…

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Aircraft radio circuit

Description. Here’s a low cost radio circuit that can be used to listen to the radio conversations between aircrafts. The radio circuit based on transistor 2N918 and diode 1N82 receives in the 220Mhz to 400Mhz range. Capacitor C1 and inductor L1 forms the tank circuit for tuning. Diode D1 performs the detection. Transistor T1 performs the necessary amplification. The out put audio signal is just enough to drive a small headphone. For driving speakers. Circuit diagram with Parts list.  Notes.  Use a 45cm long wire for antenna, For L1 make 2 turns of 22 AWG magnetic wire on a 5/32…

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AM Transmitter circuit

Simple AM Transmitter Description Here is the circuit diagram of a simple AM transmitter circuit that can transmit your audios to your backyard.This circuit is designed with limited  power output to match the FCC regulations and still produces enough amplitude modulation of voice in the medium wave band to satisfy your personal needs.You will love this!. The circuit has two parts , an audio amplifier and a radio frequency oscillator. The oscillator is built around Q1 (BC109) and related components. The tank circuit with inductance L1 and capacitance VC1 is tunable in the range of 500kHz to 1600KHz. These components…

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Single chip FM transmitter circuit

Single chip FM transmitter Description Here’s a single chip FM transmitter circuit using Maxim semiconductors IC MAX2606. The MAX2606 is a compact, high-performance intermediate frequency VCO specially designed for wireless communication circuits. They have monolithic construction with low-noise and a low-power operation in a compact 6-pin SOT23 packing .Th1s low-noise IC feature an on-chip varicap diode and feedback capacitances that avoid the need for external tuning components, making the MAX2606 perfect for portable systems. Only an external inductor is needed to set the oscillation frequency.In addition to this, an integrated differential output buffer is also there for driving a mixer…

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Single Chip FM Radio circuit

Single Chip FM Radio Description. Here is a compact low cost FM radio circuit using IC TDA 7000. This circuit is designed as per the data sheet and the result is excellent.Ideal for all category of electronic enthusiasts. The TDA7000 is a monolithic integrated circuit for mono FM portable radios, where a minimum on peripheral components is crucial. The IC TDA 7000 has a Frequency-Locked-Loop system with an intermediate frequency of 70 kHz. The intermediate frequency selectivity is achieved by active RC filters. The only function which needs alignment is the resonant circuit for the oscillator, thus selecting the reception…

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Direct Coupled Radio

Direct Coupled Radio Circuit Description Here is the circuit of an excellent direct coupled radio ideal for listening to near by stations.The circuit uses Q1 as a diode detector and first audio amplifier.The detection is across the first emitter base junction which operates as a diode.The base emitter capacitance provides the radio filtering.The resistor R1 is adjusted to obtain the least distortion with consistent volume.Transistors Q2 and Q3 also serve as audio amplifiers. Radio Circuit Diagram with Parts List Notes For L1 use a center tapped ferrite antenna coil used AM receivers. Battery is advised to power the circuit to …

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Simple Radio Circuit using Op Amp

Simple Radio Circuit Description This is a low cost simple radio circuit  based on op amp which can be used to listen to nearby stations. A simple op-amp radio basically consists of a crystal radio along with a fairly sensitive audio amplifier. The audio amplifier is able to receive strong stations around Los Angeles with a minimal 15 foot antenna. Stronger signals are always provided by longer antennas.But the main disadvantage is that in the case of long antennas the stronger signals provided may produce a noise as it could be heard in the background of the weaker signals. In…

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Radio Collar Transmitter

Radio Collar Transmitter Description This is the circuit diagram of a radio transmitter suitable for fitting on radio collars.The circuit transmits a pulse in the FM between band 88MHz to 105Mhz , which can be adjusted.IC Ne 555 is wired as an astable multivibrator for producing the tone.L1 ,C3 and Q1 forms the modulator.Q2 performs the final power amplification. Notes For the inductor make 5 turns of .5 mm dia insulated copper wire on a standard ball pen refill.Remove the refill and make a tap at the center of coil.To vary transmission frequency experiment with number of turns.Careful! what ever…

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Long Range FM Transmitter

How to make a long range FM transmitter at low cost Description The use of transmitters which have a more powerful output than the ‘flea-power’ are sometimes required when there are many obstacles in the path of the surveillance transmitter and monitoring station receiver, or the distance between them is too far so as to make a low powered device feasible. Whereas a typical micro transmitter will produce an RF power in the order of just a few milliwatts, i.e. a few thousandths of a watt, the VHF-FM transmitter described has a power output of between around a half and 2 watts, depending on the power source, which…

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