Show higher value rheostats are regarded advisable when typo type tubes are used as ag detectors it Is advisable to use a filament rheostat of about 30 ohms because although these tubes are not very critical to changes in voltage they are most sensitive fIve tit al urne oe particular point A cohin C bin rheostat does docs not permit the ane regulation of voltage that Is obtained with one of higher resistance in some cases cas esthe the point at which the tube oper operates ittes most efficiently Is much lower lowe ethan than the rated hafed voltage radio news |