Handy man's workshop and laboratory . ii I l ( «« I < i c=p KEYS ALWAYS * J OPEN. Fig. 231—An open-circuit telegraph system ¥ accompanying diagram will obviate all the trouble, enabling themto call other stations, and at the same time the keys are alwaysopen; the cells being used only when the instruments are beingoperated. Any number of additional instruments may be put onby following the method indicated in the diagram.—94 A TEST FOR TELEPHONES A great many so-called high-resistance telephones have re-cently appeared on the market for use with wireless of these have been fo
Handy man's workshop and laboratory . ii I l ( «« I < i c=p KEYS ALWAYS * J OPEN. Fig. 231—An open-circuit telegraph system ¥ accompanying diagram will obviate all the trouble, enabling themto call other stations, and at the same time the keys are alwaysopen; the cells being used only when the instruments are beingoperated. Any number of additional instruments may be put onby following the method indicated in the diagram.—94 A TEST FOR TELEPHONES A great many so-called high-resistance telephones have re-cently appeared on the market for use with wireless of these have been found to be wound with German-silverwire. This gives the required resistance at a greatly reducedcost. This fraud can be easily detected, even if the German silver is 292 HANDY MAN S WORKSHOP AND LABORATORY concealed under an outer layer of copper wire, as follows: Bal-ance as nearly as possible on a sensitive Wheatstone bridge, sothat the indicator comes to rest at or near the zero point. Thenhold down the key for about a minute, allowing the battery cur-rent to flow through
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Keywords: ., book, bookcentury1900, bookdecade1910, booksubjectworkshoprecipes
