(1) When the sky level is at null nominal zero, the generated torque is M=m 1×g×Ll, and m right =F×L2? Because the balance is zero.
Balance, then m left = M right. M 1? ×g× Ll= F×L2？ .
(2) When the weighing object m2 is loaded on the weighing plate, the lever deviates from the zero position, and the zero indicator has a deviation signal. After a series of conversions such as amplifier and regulator, the current I of the coil will increase, and the electromagnetic torque right will also increase together, and the lever will return to the original equilibrium position, that is, the zero position of the balance.
Finally m left = M right? , which is m2? ×g×Ll= F×L2？ Finally, the electrical signals are processed into digital signals and displayed on the display screen. The following important conclusions are drawn: what is the current intensity passing through the coil in the magnetic field? I is proportional to the mass m of the weighed object.
Extended data:
Electronic balance and its classification can be divided into the following categories according to the accuracy of electronic balance:
1. Ultra-micro electronic balance: The maximum weight of ultra-micro balance is 2 to 5g, and its scale value is less than 10-6. For example, mettler's UMT2 electronic balance belongs to ultramicro electronic balance.
2. Micro-balance: The weighing of micro-balance is generally 3 to 50g, and its dividing value is less than (maximum) 10-5, such as AT2 1 electronic balance in mettler and S4 electronic balance in Sartoruis.
3. Semi-microbalance: The weighing of semi-microbalance is generally 20- 100g, and its dividing value is less than (maximum) weighing 10-5, such as AE50 electronic balance in mettler and M25D electronic balance in Sartoruis.
4. Constant electronic balance: The maximum weight of this balance is generally 100 to 200g, and its dividing value is less than 10-5. For example, AE200 electronic balance in mettler and A 120S and A200S in Sartoruis belong to constant electronic balance on average.
5. Analytical balance: In fact, electronic analytical balance is a general term for constant balance, semi-micro balance, micro balance and ultra-micro balance.
6. Precision electronic balance: This kind of electronic balance is the general name of electronic balance with precision grade II.
Precautions:
Due to the high precision of the counterweight, there are many requirements for the environment and operation. What problems should be paid attention to in daily use and how to prolong the service life of the electronic analytical balance?
1 ? Don't put the balance weight on the side table under the air conditioner. The moved electronic analytical balance must be re-leveled, and the metrological performance of the balance must be comprehensively checked before it can be used.
2 When weighing hygroscopic, volatile or corrosive articles, tighten the weighing bottle cap and weigh it as soon as possible. Be careful not to spill the weighed items (especially corrosive items) on the weighing plate or bottom plate; After weighing, the weighed object should be removed from the balance in time, and the weighing room should be kept clean.
The same experiment should be weighed with the same balance to avoid the error caused by weighing.
levelling
1. When the horizontal bubble is above the horizontal circle, it means that the upper position of the electronic balance is high. We should rotate the two corners of the upper part of the electronic scale to make the bubbles move down.
2. When the horizontal bubble is lower than the horizontal circle, the low position of the electronic balance is on the high side. We should rotate the two corners of the lower part of the electronic scale to make the bubbles move upward.
3. When the horizontal bubble is on the left side of the horizontal circle, it means that the position on the left side of the electronic balance is on the high side. We should move the bubbles to the right by rotating the two corners on the left of the electronic scale.
4. When the horizontal bubble is on the right side of the horizontal circle, it means that the position on the right side of the electronic balance is high. We should move the bubbles to the left by rotating the two corners on the right side of the electronic scale.
Tip: Sometimes the horizontal bubble is oblique, which requires us to use several angles back and forth.
References:
Baidu encyclopedia-electronic balance