| 摘要 |
1,193,821. Current and voltage measurement. RECORD ELECTRICAL CO. Ltd. June 5, 1967 [March 14, 1966], No.11023/66. Heading G1U. A suppressed-zero measuring arrangement consists of a bridge with Zener diodes ZD1 and ZD2 in opposite arms, and resistances R2 in the other arms. An input to be measured is applied across one diagonal and a transistor amplifier A across the other, the output from this being supplied to a meter 11 to provide the suppressed zero measurement. In the current measuring system of Fig. 1, a resistor Rs is connected across the source of current to be measured to provide a load for currents below the measuring threshold. A resistor R1 across the meter has a temperature co-efficient such as to provide compensation for variations in the amplifier output with temperature. It is shown in the Specification that the current suppression level depends on both the Zener voltages and the resistances in the circuit. By adjusting the resistors, the level can be altered. A voltage measuring system is formed by including a resistor in series with the source to be measured. |
