DIY stress measuring table ---- stress measuring instructionnt

DIY stress measuring table, Stress Measuring Instrument Keywords: UA741 pressure measurement circuit diagram Be Author: Silicone Valley The measurement stress is to attach the resistance strain chip SG1 (a probe corresponding to measurement stress) to a certain portion of the object to be measured, and if the object is elongated or shortened, the resistance change of the strain sheet can cause the resistance of the strain sheet, by resistance change It can be converted to a voltage change and then read from the stress measurement table. The self-made stress measuring table uses an analog voltage meter or a digital voltmeter as a readout device, as long as it is full of IV DC. The circuit uses a single-running chip IC741 (LC3) to enlarge the output voltage of the Horses Pyston Bridge (consisting of RL, R2, R3, and SG1 strain resistance). Since the nominal resistance of the SGI is 120Ω, both RL, R2, and R3 should be 120Ω to make the bridge balance. The RL ~ R3 resistance difference should be better than 0.L%, making any temperature variations not to cause a change in reading. Be The sensitivity of the op amp can be adjusted by VR2, which can make this circuit respond to different stress amplitudes. The + 5V and -5V supply voltages are provided separately from the regulator chips IC1 and IC2, and the output of IC3 is enlarged from the output of the Newton Bridge. The strain is pasted to the surface of the L50 × 10 × 1 square millimeter plastic strip pad, and then the strain pin is inserted into the socket of the stress measuring table, and then measured with a digital voltage gauge. The stress measuring table should be set first, so that the strain sheet is about 0.5 V when the strain sheet is in force. If the plastic strip is bent, the strain sheet is slightly elongated (elongate stress), the output voltage should be increased; if the plastic strip is bent to reduce the stress sheet (compressive stress), the output voltage should be reduced. Settings can be done as a tuning tool with a multi-loop fine tuning potentiometer VR1 and VR2. The adjustment steps are as follows: 1. The multimeter is set at 0V to 5V DC voltage range; 2. The SL is placed in the "LO" position; 3. Adjust the VR1 and VR2 until the readings on the multimeter is about + 0.5V; 4. While your bending plastic strip, check if the reading on the multimeter is changed: 5. The multimeter voltage is switched to 1V, bend the plastic strip, and then record the voltage change response. If the response is not sensitive enough, SL can be changed to the "HI" location. Adjust the VR1, to ensure that the reading is still within the range of the multimeter. Increases the value of R6 and R7 to increase gain. After the adjustment is completed, the strain sheet is removed from the plastic strip, and the stress measurement table can be officially used. When used, attach the strain chip SG1 in the need to measure the stress, and then read the stress from the multimeter.