| 摘要 |
<p>PURPOSE:To easily adjust the gain of an amplifier and to take a measurement with high accuracy by providing a power source, a multiplexer, a switch, etc. CONSTITUTION:Switches 310 and 311 are closed and the circuit of the resistance bulb 11 is connected to the power source 450 individually. Then when a 1st switch 500 is closed, the power source 450 is connected to the circuit of the resistance bulb 11 and a current from the power source 450 flows to the ground side through the path consisting of a conductor resistance 110, the resistance bulb 1, and a conductor resistance 112. Here, the switch 500 and a 3rd switch 503 are closed and a capacitor 700 as a 1st signal holding means samples the stationary value of a voltage drop based upon the current following from the power source 450 to the circuit of the resistance bulb 11. Then a 2nd switch 501 and the switch 503 are closed and a capacitor 701 as a 2nd signal holding means samples the stationary value of the voltage drop based upon the current flowing from the power source 450 to the circuit of the resistance bulb 11. Thus, the resistance value of the resistance bulb 11 due to temperature variation is detected from the voltage variation and the resistance of the circuit of the resistance bulb 11 at this time can be ignored.</p> |
