For the measurement of the piezoresistor, some people say yes, some people say no, the use of varistor is generally in the circuit in parallel, when drastic changes in the voltage across the varistor will short-circuit and inside current fuse, play a protective role to a certain extent. The role of varistor in the circuit, a small series mentioned in the beginning, it is used for power supply high voltage occurs in the protection and the role of regulator, when measuring the multimeter position in the 10K file, and then put the probe connected at the two ends of the resistance, the multimeter can show the varistor if the resistance, far more than this value if the varistor has been damaged.
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How do you measure a varistor? The use of varistors is as follows:
1. Switch the knob to the following position before use:
"Voltage selection": 100V
"Test options": lmA
"Pressure sensitive switch": off
"Drain knob": turn the clock backward
2. Switch on the "power". The digital table on the upper right shows the constant current source output voltage. At this time, the digital table on the top left shows 000.
3, according to the nominal value of varistor suitable voltage range, access to the tested element, connect the pressure sensitive switch at the digital table display is the varistor voltage element is lmA value; if you want to test V0.1mA press 0.1mA readings.
4, the leakage current test voltage and voltage selection switch of coaxial test, leakage current, need to write down the V1mA varistor readings, and press the "leakage" key test "in" at the same time, clockwise leakage current voltage regulation knob, the reading and reading at the same V1mA, the current meter reading is for the element value of leakage current under 83%V1mA. When the leakage current is tested, the drain current voltage knob shall be turned counterclockwise and at the lowest voltage output. The error in the leak current test will cause the ammeter to be overloaded.
5, "measuring pressure ratio" and "test voltage voltage selection switch of coaxial, according to the V1mA value to select the appropriate voltage range, press the" test "in the" pressure "button, and adjust the compression ratio of the zero potentiometer (two coarse, fine, make a left pressure) than the number of characters to 0, and then press the pressure ratio according to the table, the display value is the voltage ratio.
Reading method of pressure ratio (example):
Table shows the actual ratio
(1) 19991.1999
(2) 6021.0602
(3) 3051.0305