Digital multimeter and pointer multimeter which anti-interference strong
Say I feel, the earliest I use the pointer multimeter, use, such as resistance file sometimes need to adjust the zero, measuring voltage, first by the high-grade level to start measuring, in order to prevent burning the table, in addition, the measurement also need to put the smooth, read the value of the line of sight should be perpendicular to the surface of the scale disc. It is subject to human and environmental interference.
On the contrary, the digital multimeter does not have the above shortcomings, and the input impedance is large, do not worry about burning the meter.
Digital multimeter on the use of environmental requirements are relatively low, applicable to a wide range of anti-interference ability, see the parameters intuitif.
Analog multimeter is larger, inconvenient to carry, high requirements for the use of the environment, anti-interference ability is poor, see the readings is not convenient, but the accuracy is higher.
Anti-interference ability is of course pointer multimeter is better, digital multimeter measurement of some electrical parameters such as inverters within certain points of voltage readings will jump, no way to read, pointer multimeter does not have this problem, but the degree of accuracy and ease of use than the degree of digital table is poor. In short, the two have their own advantages and shortcomings.
Pointer type table has two kinds of internal and external magnetism, by the influence of static electricity error is too large, do not believe you in the dial glass on the hands of the needle will not return o the digital table is good to use a point, but each has its own strengths and weaknesses.
The heating tube can be regarded as a purely resistive load, the current flowing through the heating tube is purely active current. With the AC current measurement function of the clamp multimeter to measure out the current when the heater is working. With the current value multiplied by the rated voltage of the heating tube to arrive at the value is the power of the heating tube (wattage).
For example, an electric heating tube rated voltage is 220 volts, the measured current is about 2 amps, then the power of the heating tube is about four hundred and forty watts. If the rated voltage of the heater is 380 volts and the measured current is about 1 amp, then the power of the heater is about four hundred watts.
Satu thing to keep in mind here is the rated voltage of the heating tube. A heater rated at 220 volts plugged into 380 volts will quickly burn out the heating wire because of the high voltage. Conversely, the rated voltage is 380 volts of the heating pipe into the 220-volt voltage, will not reach the rated voltage and not reach the rated power.
