SU444993A1 - Thermistor wattmeter microwave - Google Patents

Description

one

The invention relates to an ob-1 region for measuring a low microwave power,

Known thermistor wattmeters microwave, containing a thermistor 5 bridge, a heating generator, a power source and an indicator device. They are inconvenient in operation due to the need to perform double manual balancing of the bridge with each measurement, have low accuracy at the lower limit due to the use of low sensitivity arrow null indicators, 15

The purpose of the invention is to reduce the measurement error while simplifying the design.

To do this, in the proposed thermistor power meter, the power source of the bridge or bridge is made in the form of a current stabilizer, and the indicator, made for example in the form of microamperes. meters with a set of shunts, connected between the power point of the bridge and the control-25

| L impedance, for example, a transistor, regulating the signal to which the amplifier, included in the zero diagonal of the bridge, is fed from the output.

The drawing shows a diagram of the proposed wattmeter

It consists of a current regulator I, a thermistor bridge 2, a generator for heating a thermistor and an indicator made of a switch device 4 with a shunt 5 (one or more), a DC amplifier 6j and a controlled resistance i (transistor) 7, ;

The wattmeter works as follows.

Before supplying the measured power to the thermistor, the compensation current is set to zero, which is achieved by adjusting the level of the heating generator 3. At the same time, due to the change in heating, the state of balance of bridge 2 occurs at a current equal to the current of the stabilizer I ,. and the indicator current is equal to i

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When the power is supplied out of power, the teristor overheats, and the tracking system, striving to maintain the balance of the bridge, opens the transistor 7, as a result of which current flows through the indicator circuit, and the current of bridge 2 decreases accordingly, reducing the initial heating of the microwave, The indicator is calibrated in units of measured power.

SUBJECT OF THE INVENTION A microwave thermometer wattmeter containing a thyristor bridge, a heating generator, a power source and an indicator, characterized in that, in order to reduce measurement error while simplifying the design, the bridge power supply is made in the form of a Walk stabilizer parallel to which the indicator is connected.