How a multimeter measures current
A multimeter is one of the necessary tools for making hardware. The multimeter is powerful and can measure voltage, resistance, diodes, etc., and it is also very simple to measure current. The multimeter needs two very critical issues when measuring current: 1) Set the multimeter's gear to the current gear (need to pay attention to AC or DC); 2) Connect the multimeter's test leads to the current jack.
1. Select the appropriate current gear
The ammeter has a large rotary dial where the various signal quantities to be measured can be selected. Before measuring the current, it is necessary to find out whether the measured current is AC or DC. Set the dial to the appropriate gear, and select the appropriate range after estimating the current size.
2. Select the current jack
This question is critical and easily overlooked. When measuring voltage, resistance, diode and other signals, the red test leads are all connected to the VΩ gear. When measuring current, you need to connect the red test lead to the current jack. The current jack is divided into A ampere and mA milliampere. After correctly estimating the size of the current value, select the A or mA jack, and the position of the black test pen remains unchanged.
3. String into the circuit under test and read
The ammeter needs to be connected in series in the circuit under test, and the current needs to flow in from the red test lead and flow out from the black test lead. Then there is the reading. In some meters, the AC gear and the DC gear are put together, and there is a yellow button to switch. After switching to the appropriate gear, the current value can be read on the display.
Whether it is a clamp meter or a high-precision digital multimeter, the operating principle of measuring current is the same. Remember a few key points in the process: gear, jack, and series connection.
