It is based on ‘griffen pattern which is highly suitable for reflecting ‘besto ballistic galvanometers. it consists of a heavy steel cabinet made from s.w.g 20 sheer of size 6”x 31/2” wit printed aluminum panel on the top. in this steel cabinet, a step down transformers of 6 volts. 3.5 amps is enclosed, which is suitable for the lamp house.
the lamp house is made from aluminum-sliver alloys, machined and finished in pleasing duco paint. it is fitted with special 6 volts 30 watt bulb which is connected to the transformers with a male-female detachable plug.
the lamp house is fitted with a rack and pinion arrangement for focusing. a double convex lens made from imported glass of 18mm diameter of 4” focal length is used in it for better results.
the lamp house can slide up and down along the vertical box. the inclination of the lamp can be adjusted in vertical plan.
bright light through the convex lens falls on the concave mirror of the ‘besto ballistic galvanometer and forms a bright spot on the translucent perspex scale fitter in a special bracket above the lamp house with is divided into 25-0-25 cm and 0 to 50cm.