Useful Tips

Radio Record, Volume III, Issue 27, 17 January 1930, Page 30

Useful Tips

_ Adjusting Plate: Current. T is always ‘worth while’ introducing a. milliamnieter into the "B" battery supply circuit.and making adjustments’ with a grid-bias voltage until you find out what is the minimum "B" battery; current which will-giye satis-. factory reproduction, ° The saving in "BR" battery current which ean be effected. in this way-not ‘only without any ‘adverse ‘influence upon ‘results but éven ‘with improvement ins the ‘sameis often quite surprising to experimenters. who.have never taken the trouble to determine what current, is passing from their."B" battery. Even though economy is of little or, no. impor where an ‘eliminator is* employa?® is still desirable: to -give careful attention to the question of correct grid bias because of the improvement which: is thereby obtained in reproduction. A. Useful ° Device. A SOLDERING board is a very convenient addition to any home wireless ‘workshop. * It should ‘consist of a piece of ‘stou "poard not less than 12in. square, on which is mounted:a wire cradle’ for ‘a~hot. soldering iron (this can’ be ‘made of pieces of heavy: wire bent to suitable shape ‘and: driven into ‘the wood) a reéess into which the tin of soldering flux can ‘be ‘pressed so as to’ avoid‘ any: ‘possibility’ ‘of ‘it being pushed. off the board, and the lid of a large cocoa or coffee tin attached firmly ‘to ‘the baseboard at some convenient point by a couple of nails. Into this last. a, few pieces of solder should be dropped; and subsequently jt should be used’ for any odd. bits of: solder that are not ‘at the moment: being used. After the iron is heated it can be cleaned, dipped into the. soldering flux, and tinned quickly in the'tin lid referred ‘to. This latter will also serve to recharge it b with solder as often as required. Drilling Mica. . ‘MATEURS sometimes find it necese _. Sary to take upon. themselves the task of: making their own fixed eon densers for: special. purposes, .and,’ in such cases, trouble is. very frequently experienced . in drilling a clean hole through the mica diélectric: sheets, : especially near- the corners. or edges of the mica, The difficulty is; of course, that mica is brittle and thus ‘it: tends to chip away when drilled. An easy way out of the difficulty, ‘however, con- sists. in: sandwiching the mica ad between .two- perfectly flat. off wood which are then clamped in a or held together tightly ‘by some other means... :