Handicraft for handy boys; : practical plans for work and play with many ideas for earning money, (1911)
Hall, A. Neely (Albert Neely), b. 1883, Hall, Norman P., ill · Boston, : Lothrop, Lee & Shepard · leaf 282
ne or a pair oftelephone receivers, detector, tMumg-coil, and condenser, towhich a pote^itiometcr and a dry battery and a secondcondenser must be added when a detector of the micro-phone type is used. Of these The Telephone Receivers must be purchased; theremaining instruments can be made by any… … Coil-Sl»der TO-DetectorTO-Battery . 0 POTENTIOMETEfy /or
Woodwork · Toys · Amusements
Internet Archive · Boston Public Library · Public Domain Mark 1.0. Free to use for anything.
![An illustration from [Graphophone patents] (1878)](https://img.insideoutlibrary.com/img/200/ia-graphophonepaten07unit-511-343.webp)
