Tips and Jottings

Radio Record, Volume V, Issue 25, 31 December 1931, Page 15

Tips and Jottings

S semi-variable condensers are not usually intended to withstand high voltages, it is not wise to place them between filament and plate, oF where the full voltage of the battery, will be impressed upon them t HEN using a semi-variable condenser in the output circuit, or where it may be called upon to withstand @ considerable voltage, it is a good pre caution to introduce a large fixed cons denser in series with it. WHEN taking readings with a volt. , meter, remember that the instrus ment will take some current whilst the reading is being made, and only a high resistance voltmeter can give an approximately accurate reading. A GOOD rough-and-ready test if the insulation of a large condenser is to charge it from a battery and then stand ‘it aside over night, and in the morning see if a spark can be obtained by touching the terminals. If so the condenser is O.K. AYTER cutting three-ply wood it generally has rather splintery edges, and the simplest and neatest way te round these off is to lay a fairly large piece of coarse sandpaper flat on the bench and rub the wood along this, 80 cleaning up the edges.: :