rheostat; potentiometer; adjustable resistor
Technical term for a variable resistor used to control current or voltage. 可変抵抗器 is a common synonym.
See also: 可変抵抗器
I adjusted the circuit current using a rheostat.
Synonym; 可変抵抗器 is more common in modern technical writing, while 加減抵抗器 is an older or alternative term.
Compound of 加減 (adjustment) + 抵抗器 (resistor). The exact historical derivation is uncertain, but the term is formed from standard Sino-Japanese components.