Power testing load device and method for testing output power of shortwave therapeutic apparatus

Abstract

The invention discloses a power testing load device and a method for testing the output power of a short-wave therapeutic instrument. It includes a case and a case cover. There are positive and negative terminals, pointer ammeter, silicon photocell and adjustable potentiometer on the support plate, a lamp holder on the lower support plate, an incandescent bulb on the lamp holder, and round aluminum bulbs on both ends of the lower support plate. Each circular aluminum sheet is connected to the lower support plate through a connecting iron sheet; there are heat sinks and four series non-inductive resistors on the back of the chassis, one end of the four series non-inductive resistors is connected to the negative pole of the lamp holder and the negative terminal, and the other The positive pole of the lamp holder at one end is connected to the positive terminal; the silicon photocell is close to the incandescent bulb and electrically connected to the pointer ammeter, and the adjustable potentiometer is connected in series between the silicon photocell and the pointer ammeter. The invention has the advantages that it does not need to be directly connected with the signal line, does not interfere with the resonant circuit of the short-wave therapeutic apparatus, has small test errors and accurate test results.

Description

technical field [0001] The invention relates to a power test load device, in particular to a power test load device and a method for testing the output power of a short-wave therapeutic apparatus. Background technique [0002] The output signal frequency of the short-wave therapy device is 27.12MHz, the power is 200W, and the wavelength is 11.06 meters. Usually, in order to detect the power of the output signal of the short-wave therapy device, there are generally three methods as follows: [0003] Method 1: If figure 1 As shown, the resistor R is connected in parallel at the output end of the short-wave therapy device, and the voltage value U at both ends of the resistor R is read with an oscilloscope. According to the power W=U² / R, the output power of the short-wave therapy device can be obtained; but the disadvantage of this method is : When the oscilloscope is connected to both ends of the resistor R, since the oscilloscope probe has distributed capacitance, it will aff...

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Problems solved by technology

[0003] Method 1: If figure 1 As shown, the resistor R is connected in parallel at the output end of the short-wave therapy device, and the voltage value U at both ends of the resistor R is read with an oscilloscope. According to the power W=U² / R, the output power of the short-wave therapy device can be obtained; but the disadvantage of this method is : When the oscilloscope is connected to both ends of the resistor R, since the oscilloscope probe has distributed capacitance, it will affect the distributed capacitance of the resonance of the short-wave therapy device, and then have a lot of influence on the output frequency and power of the signal, resulting in a large test error;

[0004] Method 2: If figure 2 As shown, connect resistance R in parallel at the output end of the short-wave therapy device, use an oscilloscope + high-frequency current transformer L to test the current value I on the signal line, and according to the power W=I²*R, the output power value of the short-wave therapy device can be obtained; However, the disadvantage of this method is that the frequency range that can be tested by the oscilloscope + high-frequency current transformer does not exceed 60MHz, while the fundamental frequency of the short-wave therapeutic instrument is 27.12MHz, and the signal output is expanded according to the Fourier series, and the fundamental frequency is 27.12MHz , the frequency of the frequency multiplier signal is an integer multiple of the fundamental frequency, so the current transformer cannot test the frequency component of the frequency multiplier signal, resulting in a large error in the test results;

[0005] Method 3: If image 3 As shown, the resistance R is connected in parallel at the output end of the short-wave therapy device, and the current value I on the signal line is tested by connecting a high-frequency ammeter in series with the output signal line. According to the power W=I²*R, the output power of the short-wave therapy device can be calculated. But the disadvantage of this method is: the ammeter is connected in series in the signal line, which will affect the distributed capacitance of the resonant circuit of the short-wave therapeutic instrument, and then affect the frequency and power of the output signal, resulting in large errors in test results

[0006] The problems existing in the above three test methods are mainly summarized as follows: When using a high-frequency ammeter or an oscilloscope to detect, the capacitance of the instrument itself will affect the resonant capacitance on the output signal line, which will affect the self-resonance of the short-wave therapeutic instrument, making the frequency of the output signal Or the power changes; use a current transformer to test the current value on the output signal line, the frequency range that the current transformer can test is not greater than 60MHz, and the measurement range is limited

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