Sensitive FM Field Strength Meter Or RF Detector

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In this project, we are demonstrating the FM Field Strength Meter or RF detector circuit. This is a project of exceptionally sensitive FM field strength meters or we can likewise say them RF detectors. A radio frequency (RF) detector is a device used to detect the RF waves either in a wireless or wired (on RF Cable) physical transmission medium. Both the circuits can be utilized to quantify the field or signal quality of FM transmitters.

The circuits are very sensitive and can recognize a low-power transmitter from 8 to 10 meters away and give a visual and sound signal by actuating an LED and a piezo buzzer.

CA3140-Bi-CMOS-Operational-Amplifier

Hardware Components

The following components are required to make RF Detector Circuit

S.noComponentsValueQty
1ICCA31401
2PNP Transistor2N44031
3Piezo Buzzer1
4Diode1N40071
5Antenna30 Inches1
6LED1
7Coil6 turns1
8Resistor1M, 470Ω, 1K1, 1, 2
9Battery9 – 12V1
10NPN Transistor2n4401
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CA3140 Pinout

CA3140-Pinout

For a detailed description of pinout, dimension features, and specifications download the datasheet of CA3140

RF Detector Circuit

field-strength-meter-circuit-Circuit-Diagram-Schematic

Hardware Components

The following components are required to make Field Strength Meter Circuit

S.noComponentsValueQty
1CA3140CA31401
2Transistor2n39041
3Battery9 – 12V1
4Piezo Buzzer1
5Diode1N40071
6Antenna85 cm1
7LED1
8Coil6 turns1
9Resistor1K, 1M, 470Ω1, 1, 1
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Field Strength Meter Circuit

Circuit Operation

In this section, we have discussed the circuit operation of the FM Field Strength Meter. The field strength meter or RF detector circuit has appeared in figure 1 is a basic circuit utilizing not more than 8 segments and a battery. The circuit is worked around a CA3140 IC, which is an operational amplifier. There isn’t a lot of difference between the two circuits yet just the 2N3906 PNP transistor utilized at the output of the figure 2 circuit to additionally increase the sensitivity. L1 is an air-cored coil and can be made effectively by winding 6 turns of #24 enameled wire on a 5mm structure. Make sure to expel the insulation from the two parts of the enameled wire to make a solder connection. For radio, wire utilizes an 85 centimeters adjustable antenna.

Applications and Uses

There are many applications for FM Field Strength Meter or RF detector but primarily it is used to measure and control RF power in wireless systems.