A device for modulating the intensity of light rays generated from a gas laser in which an input modulating signal is supplied to a switching element included in a modulating current supply source connected across a gas laser discharge tube to control the discharge current and hence modulate the laser light output. The gas laser discharge tube is eventually subjected to the influence of a magnetic field so as to stabilize the laser light output and modulating characteristic.

Device for modulating intensity of light rays generated from gas laser

1,108,089. Tap changing transformers. J. H. CALVIOU, R. G. CLITHEROE and D. D. SILVESTER. 3 Nov., 1966 [17 Sept., 1965], No. 39790/65. Heading H2H. A transformer having on-load tap changing on its primary winding for coarse voltage control has a resistor R8 variably shunted by a pair of reverse parallel thyristors for fine voltage adjustment. Inter tap circulating current is limited by a resistor Z. Controls for the fine and coarse voltage variations may be ganged to provide a smooth transistor. The thyristors are fired by pulses having a high frequency relative to that of the supply e.g. 3 kc./s. with a mark space ratio of 1 : 15.

Silvester David Denys

Papers

Voltage regulation system