The working principle and application of electromagnetic radiation detector

Abstract: Electromagnetic radiation detectors have been widely used in our lives. This article mainly introduces the use method of the electromagnetic radiation detector, the working principle of the electromagnetic radiation detector and its application, and explains the characteristics of the electromagnetic radiation detector in detail.
Introduction to electromagnetic radiation
Electromagnetic waves (also known as electromagnetic radiation) are electric and magnetic fields that oscillate in phase and are perpendicular to each other in the form of waves that move in space, and their propagation direction is perpendicular to the plane formed by the electric and magnetic fields, effectively transferring energy and momentum. Electromagnetic radiation can be classified according to frequency, from low frequency to high frequency, including radio waves, microwaves, infrared, visible light, ultraviolet light, X-rays, gamma rays, and so on. The electromagnetic radiation that the human eye can receive has a wavelength between 380 and 780 nanometers and is called visible light. As long as it is an object whose temperature is greater than zero degrees, it can emit electromagnetic radiation, and there is no object with a temperature equal to or below zero in the world.
The working principle of electromagnetic radiation detector
  As shown in Figure 1. The sensitive element used in the detector is an inductance coil (L1) connected to a field effect transistor (T1). T1 is polarized at the beginning of its conductive area through a fixed resistor (R1) and a variable resistor (AJ1) connected in series. The amplified electromotive force generated in L1 will appear on the drain of T1. The amplified signal presented on the terminal pin of the resistor R2 is sent via the capacitor C1 to a second amplifier stage arranged on the common emitter established around the NPN transistor T2. The amplitude of the signal presented on the collector of T2 certainly depends on the surrounding radiation intensity; if you use an oscilloscope to test, you can see a voltage waveform above 100mV on the collector of T2. Capacitor C2 is a coupling capacitor, which sends the amplified signal of T2 to T3, and at the same time acts as a DC block.

The base of T3 establishes a bias voltage through fixed resistors R5, R6 and variable resistor AJ2. Adjusting AJ2 can make T3 reach the non-radiation cut-off point, thereby extinguishing the light-emitting diode D1 in the collector circuit. When the radiation reaches a certain intensity, the negative half wave of the output signal of T2 will turn on T3, thereby illuminating the light-emitting diode D1. The resistor R7 can limit the current through the light-emitting diode D1.
Because the detector is only used to determine the range of radiation pollution, a simple switch button (P1) should be set. Capacitor C3 is used for power supply (BAT1) filtering.
Application of electromagnetic radiation detector
Electromagnetic radiation detector is mainly used for radiation measurement of electrical appliances, high-voltage lines, base stations, etc. in daily life, which can effectively help people stay away from radiation sources and avoid radiation hazards!



How to use electromagnetic radiation detector
1. Press the "power switch" for a short time to turn on the machine, the default is "magnetic field radiation intensity" detection, the alarm will sound if it exceeds 2 milliGauss; long press "detection mode switch" and do not relax, about two seconds later, switch to "electric field radiation Intensity" detection.
Note: This instrument is a high-precision measuring instrument. Due to the earth's magnetic field, the instrument may occasionally display very short values or alarms. This is not a malfunction.
2. Hold the electromagnetic radiation detector in your hand, aim the "test area" at the object to be tested, and slowly move closer to the object until it actually touches the object. The closer you are to the object to be tested, the intensity of the electromagnetic field or electric field will change. As it increases, the alarm frequency becomes faster.
3. In the measurement, try to change the angle and position of the object to be measured by the instrument to obtain the reading value.
4. If the object to be tested is turned off during the measurement, in the "magnetic field radiation intensity detection" mode, the reading should return to zero; in the "electric field radiation intensity detection" mode, some objects can still detect electromagnetic waves The signal, which belongs to the external electromagnetic wave signal received by the item, is not harmful to the human body.
5. Press "Alarm Settings" for a short time to set the alarm sound on and off.
6. Press "Peak Lock" for a short time to set to open and cancel the peak lock function. The peak lock function can lock the value during the detection process.

Product features of electromagnetic radiation detector
1. Portable design, light weight, easy to operate with one hand, easy to move or measure on site
2. Innovative circuit components are used to ensure that the performance of all equipment is still very reliable under extreme conditions
3. Very high linearity degradation and level limitation (No.: DE19809784 and DE10317805)
4. Built-in high-precision electric/magnetic compound sensor, high sensitivity and fast response
5. Fully compensated frequency response, provided measurement results
6. Real-time display of LCD screen, direct display of the total exposure value within the measured frequency range
7. Built-in signal strength prompt speaker (the size of the prompt sound is proportional to the strength of the electromagnetic field), which can effectively help identify the signal source and quickly locate the signal
8. Low battery warning and automatic shutdown function when idle