4.2.7 Appendix 1 FB308 type electricity meter refi...
1)Experimental instrument
The FB308 type electricity meter refit and calibration experiment instrument is designed including circuits and components such as a working power supply,a standard electric meter,a refitted meter,a zeroing circuit and resistance boxes.The diagram of its panel is shown in Figure 4.2.6.Students can refit the pin-type micro ammeter to ammeters,voltmeters and ohmmeters with different ranges through connecting the circuits.The instrument is convenient to use and manage,and students’practical ability can be cultivated by operating this device.
Figure 4.2.6 Panel schematic diagram of the electricity meter refit and calibration experiment instrument
2)Main parameters of the instrument
(1)Power supply:This device has two gears:0～2 V and 0～10 V.The output voltage is continuously adjustable and the gear can be changed by a button switch.The output voltage is monitored by a pin-type voltmeter.The full scale value of the voltmeter is synchronized with a range switch.
(2)Refitted gauge head:It has a wide surface gauge head,100 μA measuring range,about 1.6 kΩ(or 2.2 kΩ)internal resistance and 1.5 accuracy rating.
(3)Standard voltmeter:
Range:20 V,
digital voltmeter,0.1% accuracy.(https://www.daowen.com)
(4)Standard ammeter:
Three ranges:200 μA,2 mA,20 mA,
digital ammeter,0.1% accuracy,button switch for switching range.
(5)Resistance box:
0～111 111 Ω,0.1 Ω resolution.
3)Tips for users
(1)There are current-limiting protection measures inside the instrument,but please avoid the short circuit(or near short circuit)of the working power supply to prevent unnecessary losses such as instrument components.
(2)During experiments,please pay attention to whether the output range of the voltage source is correct.The 0～10 V range is generally used for voltmeters refit and the 0～2 V range is recommended for refitting ammeters and ohmmeters.
(3)The instrument is designed to open.Please notice connecting the plug-in line:the refitted gauge head only allows small current below 100 μΑ.And the gauge head will be damaged when overloaded!It is necessary to carefully check the wiring and circuit parameters before connecting the refitted gauge head.
(4)The instrument is equipped with high-reliability and long-life dedicated connection lines.But please be careful not to use excessive force when you use it.And align the jack when inserting the cable to avoid deforming the plastic sheath of the plug.
