Archive for the ‘Radio Circuits’ Category

FM Transmitter Circuits-The BIG List

Over years we have developed a number of FM transmitter circuits with various aspects. Today I thought of listing all of them here as a single web page, so any one can easily navigate through all the radio transmitter circuits and its schematic diagrams. Simple Two Stage FM Transmitter – This is one of the most simple FM transmitter circuit you can try out on your breadboard. It has two stages served by two transistors Q1 and Q2. The first stage is the preamplifier stage where audio input signal is amplified before modulation. This stage is served by Q1 (BC108)….

Read More

PLL FM demodulator circuit

PLL FM demodulator. A simple PLL FM demodulator circuit using IC XR2212 is shown here. XR2212 is a highly stable, monolithic PLL (phase locked loop) IC specifically designed for communication and control system applications. The IC has 0.01 Hz to 300KHz frequency range, 4.5 to 20V operating voltage range, 2mV to 3Vrms dynamic range, high temperature range, TTL / CMOS compatibility and adjustable tracking range. The block diagram of a typical PLL FM demodulator circuit is shown below. The working of a PLL FM demodulator is very easy to understand.The input FM signal and the output of the VCO is…

Read More

FM Stereo Demodulator AN7415

AN7415 FM Stereo Demodulator. AN7415 is a monolithic integrated circuit that can be used in FM stereo demodulation applications. The operating voltage range is 1.6 to 7Vdc. Two AA dry cells are enough for powering this IC and it makes the AN7415 suitable for handheld FM radio applications. AN7415 has low current consumption (2.6mA), low distortion, good channel separation and high gain. The IC is available in 16 pin DIL package. Description. The circuit shown below is of a PLL FM stereo demodulator designed based on the AN7415. C1 is the input coupling capacitor which blocks any DC voltage present…

Read More

LM1800 Stereo Demodulator

LM1800 is an integrated FM stereo demodulator IC which has a number of good features integrated on it which makes it possible to design a high quality FM stereo demodulator system with excellent sound quality. The LM 1800 uses phase locked loop technology to regenerate the 38kHz sub carrier from the composite signal. The features of LM 1800 are automatic stereo/mono switching, wide power supply voltage range, good channel separation, excellent power supply rejection, no coils required, tuning can be done using a POT etc. Description: A very simple and high quality FM stereo demodulator circuit using LM1800 is shown…

Read More

AM radio circuit.

AM radio circuit using TDA1572. The circuit shown below is of a high performance AM receiver designed based on the TDA1572 IC from Philips. The TDA1572 is an integrated AM receiver circuit that has all essential circuitries like RF amplifier, mixer, IF amplifier, AGC circuit, signal strength indicator driver, audio pre amplifier, controlled oscillator etc incorporated into it. The frequency of the internal oscillator can be up to 50Hz and the IC can accept RF inputs up to 500mV. The inputs of the IC are static protected and the separately buffered, voltage controlled oscillator makes it possible to use simple…

Read More

FM receiver circuit

CXA1019 FM receiver circuit A high quality FM receiver circuit based on CXA1019 IC is shown here. CXA1019 is a bipolar silicon monolithic FM/AM radio receiver IC from Sony. Built in circuitries inside the CXA1019 include RF amplifier, mixer, oscillator, IF amplifier, quadrature detection circuit, tuning LED driver electronic volume control, detector etc. FM section of the IC is only utilized in this circuit. The IC can be powered from anything between 3 to 7V DC and can drive an 8 ohm loudspeaker. Circuit diagram. Circuit description. Inductors L1, L2 and capacitors C4, C6, C7 forms the tank circuit for…

Read More

Stereo decoder circuit

Stereo decoder circuit. In FM stereo transmission left and right channels are algebraically encoded into sum (left + right) and difference (left-right) signals. This is done in order to make the mono FM receivers compatible with the stereo transmission. The mono receiver will reproduce the summed left and right channel and the listener will hear both these channels through a single loud speaker. Stereo decoder is a circuit which is used in stereo FM receivers in order to recover the left and right channel information from the composite transmission signal. This task is achieved by adding the difference signal to…

Read More

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…

Read More

AM receiver using ZN414

Description. This is the circuit diagram of the simplest single chip AM radio. The circuit is designed around the IC ZN414Z which is a ten transistor tuned radio frequency receiver .The IC has only three leads and is available in the TO92 package. All necessary circuits required for an AM receiver (RF amplifier, detector and AGC are incorporated inside the IC).In the circuit given below, capacitor C1 and resistor R1 forms the tank circuit which is essential for tuning. Capacitor C4 decouples DC from the output of the IC and C1 bye-passes the noise. Transistor Q1 and associated components forms…

Read More

FM Radio jammer

Description. Circuit shown here can be used to jam FM radios in its vicinity. The circuit is nothing but a classic single transistor oscillator operating in the VHF region. Working principle of the circuit is very simple and straight forward. Powerful VHF oscillations from the circuit will interfere with the FM signals to nullify it. Jammer circuits like this are illegal in many countries and you must assemble this circuit on your own responsibility. This circuit is intended only for fun and i request you not to misuse it. Circuit diagram. Notes. For L1 make 6 turns of 16AWG enamelled…

Read More