GB786421A - Alternating current power pack - Google Patents

Abstract

786,421. Rectifying. SCHWARZER, H. H. G. F. March 8, 1954 [March 6, 1953; March 17, 1953; March 17, 1953], No. 6750/54. Class 38 (2). [Also in Group XL (c)] An A.C. power pack comprises a transformer 5 having its primary winding supplied from a voltage divider comprising a resistor 7 and a glow discharge stabilizer 8, and its secondary windings connected through rectifiers to relatively large condensers 1, 2 which charge up to a value determined by the peak voltage across the stabilizer. By having the stabilizer on the primary side the output volts are not limited to the peak values of known stabilizers. To remove residual ripple a voltage may be derived from the unsmoothed supply through a transformer 11, having its primary winding connected in series, Fig. 2, or in parallel, Fig. 9 (not shown), with the supply, and fed with 180 degrees reversal into the circuit beyond the stabilizer on the primary or secondary side of transformer 6. The power pack may supply amplifiers (see Group XL (c)) used in circuits connected to physiological objects. The primary winding of transformer 6 may be surrounded by an earthed screen 16, its core 17 may be earthed and the secondary windings such as 20 may be surrounded by a screen 18 connected to those secondary winding ends which carry no A.C. with respect to the amplifiers. The screen may be slotted at 26 so that it does not form a short circuited turn, its ends being connected to a variable voltage divider 29 or 31 to neutralize the small voltage induced in the screen.