| 摘要 |
The invention relates to the measurement technique and can be used for high-precision measurement of resistance.The ohmmeter contains two terminals (3, 4) for connection of the measured object, a resistor (2) having one pole connected to the first terminal (3), a constant-current source (1), to one terminal of which is connected the second pole of the resistor (2), a converter of negative resistance (5) with an input for controlling the reproduced resistance, a control input and two outputs, one of which is connected to the second terminal (4) and the second input - to the second terminal of the current source (1), a voltage comparator (6), having one input connected to the first terminal (3), and the second input - to the common point of the converter (5) and the current source (1). The ohmmeter also contains a counting pulse generator with stable frequency (7), an AND gate (8) with one output and two inputs, one of which is connected to the output of the comparator (6), and the second input - to the output of the generator (7), a digital indication unit (9), having its input connected to the output of the AND gate (8) and to the control input of the converter (5). The control input of the converter (5) is digital, and control of reproducible resistance is obtained by means of counting pulses from the output of the AND gate (8). |
