  Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f³r Berufliche Entwicklung, 201 p.)  7. Measurement Circuits  7.1. Measurement Circuits in Direct-current Installations 7.2. Measurement Circuits in Alternating-current Installations 7.3. Measurement Circuits in Three-phase Installations

### 7.1. Measurement Circuits in Direct-current Installations Voltage measurement (A) Voltage measurement (B)

By connecting in series of a resistor (Rv), an extension of the measuring range of the voltmeter is obtained Current measurement (A) Current measurement (B)

By connecting in parallel a shunt resistor (Rp), an extension of the measuring range of the ammeter is obtained. Voltage and current measurement for the determination of the resistance

The current-exact connection is used when the resistance (Rx) to be determined, is very high. Current and voltage measurement for the determination of the resistance

The voltage-exact connection is used when the resistance (Rx) to be determined is very small if the resistance Rx is calculated according to the following equation: 