If the approximate value of the measured current is not known in advance, a variable resistor can be connected in series with an ammeter in the circuit. Initially, the variable resistor resistance should be at its maximum value, and the ammeter should first use a 0-3 ampere range. After connecting the circuit, the variable resistor resistance should gradually decrease. If the current is kept within 3 amperes, the resistance of the variable resistor can be reduced to zero. If the current does not exceed 0.6 amperes, in order to improve the accuracy of the reading, the 0 梍 0.6 ampere range can be used for measurement. DC ammeters are used for measuring current in DC circuits in the laboratory. The measurement range of a DC ammeter is 0 to 0.6 amperes and 0 to 3 amperes. General DC ammeter specifications:. The instrument is a magnetoelectric system instrument The accuracy of the instrument is level 2.5, which means that when used under specified conditions, the maximum error does not exceed ± 2.5% of the full scale value The operating conditions specified for the instrument are: ambient temperature from 0 ° C to+40 ° C, and relative humidity not exceeding 85% The normal temperature of the instrument during use is 20 ° ± 5 ℃, and the additional error caused by every 10 ℃ change in ambient temperature from the normal temperature (20 ℃) shall not exceed 2.5% The symbols on the instrument panel are explained as follows: 2.5 indicates that the accuracy of the instrument is level 2.5. A indicates that the instrument is an ammeter. Before use, check whether the pointer is aligned with the zero point. If there is any deviation, use a zero point adjuster to adjust the pointer to the zero position. To adjust, simply turn the zero adjustment knob in the middle of the front of the meter cover. DC ammeter: DC ammeter should not be directly connected to the two poles of the battery under any circumstances to avoid burning out
Function of testing report:
1. Project bidding: Issue authoritative third-party CMA/CNAS qualification report
2. Online e-commerce platform entry: Quality inspection report recognized by major e-commerce platforms 3. Used as a sales report: issuing legally effective testing reports to make consumers more confident 4. Papers and research: Provide professional personalized testing needs 5. Judicial services: providing scientific, fair, and accurate testing data 6. Industrial problem diagnosis: Verify the troubleshooting and correction of industrial production problemsBaijian and testing process:
1. Telephone communication and confirmation of requirements
2. Recommend solutions and confirm quotations 3. Mail samples and arrange testing 4. Progress tracking and result feedback 5. Provide reports and after-sales service 6. If urgent or priority processing is requiredTesting and testing characteristics:
1. The testing industry is fully covered, meeting different testing needs
2. Fully cover the laboratory and allocate localized testing nearby3. Engineers provide one-on-one services to make testing more accurate
4. Free initial testing, with no testing fees charged
5. Self service order delivery for free on-site sampling
6. Short cycle, low cost, and attentive service 7. Possess authoritative qualifications such as CMA, CNAS, CAL, etc 8. The testing report is authoritative and effective, and is generally used in China