The head of a multimeter is a sensitive ammeter. The dial on the head is printed with various symbols, scale marks, and numerical values. The symbol A - V - Ω indicates that this meter is a multimeter that can measure current, voltage, and resistance. There are multiple scale lines printed on the dial, with the resistance scale line marked with "Ω" at the right end, zero at the right end, and ∞ at the left end. The distribution of scale values is uneven. The symbol "-" or "DC" represents direct current, "~" or "AC" represents alternating current, and "~" represents the scale line shared by alternating current and direct current. The few lines of numbers below the scale line are the scale values corresponding to the different gear positions of the selector switch.

The selection switch of the multimeter is a rotary switch with multiple gears. Used to select measurement items and ranges. The general measurement items of a multimeter include: "mA"; DC current, "V (-)": DC voltage, "V (~)": AC voltage, "Ω": resistance. Each measurement item is divided into several different ranges for selection.

The pens are divided into red and black. When using, the red probe should be inserted into the socket marked with " plus ", and the black probe should be inserted into the socket marked with "-".

The head of a digital multimeter generally consists of an A/D (analog/digital) conversion chip, peripheral components, and LCD display. The accuracy of a multimeter is affected by the head. Due to the numbers converted by the A/D chip, a multimeter is commonly referred to as a 3 1/2 digit digital multimeter, a 4 1/2 digit digital multimeter, and so on. The most commonly used chips are ICL7106 (3 and a half LCD manual range classic chip, with subsequent versions of 7106A, 7106B, 72067240, etc.), ICL7129 (4 and a half LCD manual range classic chip), and ICL7107 (3 and a half LED manual range classic chip).