电流表是测量电路中电流强度的仪表，其内阻很小、学校实验室里常用的电流表的内阻一般为百分之一至几分之一欧，使用时必须与被测电阻（或被测电路）串联， 电压表是测量电路两端电压的仪表，其特点是内阻很大，学校实验室里常用的电压表的内阻一般为几千欧至几十千欧，使用时应与被测电阻（或被测电路）并联 An ammeter is a meter that measures the current intensity in a circuit. Its internal resistance is small, and the internal resistance of an ammeter commonly used in school laboratories is generally one to one-half euro. When used, it must be measured with a resistance (or measured Circuit) series, voltmeter is a meter measuring the voltage across the circuit, which is characterized by a large internal resistance, the internal resistance of the voltmeter commonly used in school laboratories is generally thousands of euros to tens of thousands of euros, should be used with Test resistance (or circuit under test) in parallel