腐食研究における演算増幅器の応用 (その1)

演算増幅器を用いた定電流装置の試作

抄録

Operational amplifiers have been employed extensively in electrochemical measurement. This paper deals with a trial construction of a galvanostat for precisely controlling current during the tests for measuring the efficiencies of the galvanic anodes. This instrument consists of three main parts: (1) the very stable current-setting circuit in which a temperature-compensated zener diode and a precise potentiometer are used, (2) the high voltage-gain amplifier in which an OP amplifier and a power transistor are combined, (3) the regulated power supply in which two power modules are employed for the sake of easy construction. The test results showed that this instrument could control output current with the precision of ±0.2% for long period even under the condition that the ambient temperature changed by about 30°C. The theoretical amounts of electricity passed through the test cells could be measured with the precision of ±0.2%, this galvanostat being used. Consequently the efficiencies of the galvanic anodes might be determined accurately without the use of the copper coulombmeter. The electrical circuit and the simple interpretation for the circuit are presented.