GB436909A - Improvements in and relating to electrical circuit testing apparatus, more especially for wireless circuits - Google Patents

Abstract

436,909. Current and pressure meters. PERRY, F., 17, Grange Park Road, Leyton, London. June 18, 1934, No. 18055. [Class 37] An instrument for testing a number of circuits, particularly for use with wireless circuits, has an indicator corresponding to each circuit, the indicator corresponding to the circuit under test being illuminated. On the back plate of the instrument are a pair of sockets 1, 2, receiving plugs connected to the low-tension battery, sockets 5, 6 connected to the grid bias battery, sockets 9, 10 connected to the high-tension battery, and a pair of sockets 13, 14 which may be connected to a pair of wander leads. A radial switch arm carries spring contacts adapted to connect these pairs of sockets in turn to corresponding pairs of contacts 3, 4, 7, 8, 11, 12, 15, 16 which are connected as shown to an instrument i. The contacts 3, 4 for measuring the voltage of the low-tension battery are connected directly to the terminals of the instrument i, resistances w, x being connected between one terminal of the instrument and the contacts 7, 11 to provide suitable ranges of measurement for voltages of the grid bias and high-tension batteries. The switch lever carries a small lamp bulb s connected to the low-tension battery through closure of a contact u when the switch lever is moved from its initial position. The lamp s passes behind a number of apertures in the front plate of the instrument, each fitted with a distinctively coloured or marked window so as to indicate the pair of contacts that is connected to the instrument i, which has a similar number of scales correspondingly coloured or marked. A pair of sockets y adapted to receive the filament pins of a valve may be provided, so that the filament current can be measured. A contact a', operated by one of the valve pins, closes the circuit of an indicating lamp z. Another pair of sockets v to receive leads from another hightension battery may be connected in series with a resistance f and the instrument i. A pressbutton is arranged to close simultaneously the circuit of the battery under test and also a contact d<1> in series with an indicating lamp c<1>.