The development history of digital multimeter
Digital multimeters have developed slowly through history. The early multimeters used magnets to deflect the pointer dial, which is the same as the classic galvanometer; modern ones use LCD or VFD (vacuum fluorescent display, digital display provided by Beijing Jintai Keyi), analog multimeters are not difficult to find in the second-hand market, But it's not very precise, because both zeroing and accurate readings from the instrument panel are prone to bias. Some analog multimeters use vacuum tubes to amplify the input signal. Multimeters of this design are also called vacuum tube voltmeters or vacuum tube multimeters. Modern multimeters are fully
The part is digitized and is specifically called a digital multimeter. In this device, the measured signal is converted into a digital voltage and amplified by a digital preamplifier, and then the value is directly displayed by the digital display; this avoids the deviation caused by parallax when reading. Likewise, better circuitry and electronics improve measurement accuracy. Older analog meters had basic accuracy between 5% and 10%, modern portable digital multimeters can achieve ± 0.025%, and bench equipment can go as far as one part per million.
