Telecom Laboratory Services used this nanovolt detector in association with other measuring instruments to monitor the quality of its telecommunications lines and ancillary equipment and to calibrate the field equipment used to measure telephone transmission equipment. This instrument is used with a potentiometer to measure very small voltages and resistances. The unit was used from c. 1967 to c. 1990 and it was likely replaced by faster and easier to use electronic and digital test equipment.

As part of the suite of items from the Telecom testing laboratory it is an example of the analogue electrical testing equipment used in the quality control of the phone system in Australia in the 1960-1990 period. While the use of this particular nanovolt detector was related to telecommunications, similar units would also have been used in physical science research, development and quality control situations whenever very small voltages and resistances needed to be measured.

The circuitry of the detector included a guard circuit to reduce or eliminate leakage currents which otherwise could exceed the very low voltages being measured.

This instrument was used by Telecom Laboratory Services, The Boulevard, Strathfield, Sydney. Alan Ogier, Telecom lab manager, said the nanovolt detector would be used with a precision potentiometer and/or bridge.

This L&N model 9838 nanovolt detector was possibly first made in 1967. It is mentioned as a 'new' model in
Research, Industrial
v.9 1967 Jul-Dec
Magazine Division, Dun
Donnelley Pub. Co., etc

Guarded Nanovolt Detector, model 9838, with 240 volt to 115 volt transformer, metal / plastic, made by Leeds & Northrup / Ferguson, North Wales, Pennsylvania, United States of America, 1965-1980, used by Telecom Laboratory Services, Strathfield, New South Wales, Australia, c. 1967-1990

The instrument is in a black metal case with a meter, three rotary knobs, two lights, and a two position switch on the front face. The centre point of the mirror-backed meter is marked '' with numbers from 1 to 5 to the right and left and graduations marked every 0.2 of a unit. The top rotary knob selects 'CHARGE', 'OFF', 'AC LINE', 'BATTERY', 'OFF', BATTERY TEST'. It is flanked by two small yellow and red plastic covered indicator lights. The left lower rotary knob is labelled 'SENSITIVITY' with numbers from 0-10. The two position switch is labelled 'OUT' 'IN'. The switch and the right rotary knob are labelled 'ZERO SUPPRESSION'.

The back of the detector has the power lead labelled '120V' '50-60 Hz', fuse and screw terminals, two labelled 'METER', two labelled 'REC + -' and two labelled 'BA - +' and a four wire lead labelled 'INPUT'.

The transformer is used to convert 240 volts to 115 volts to power the nanovolt detector. The power lead from the detector plugs into the back of the transformer.

Made: 1965 - 1980


Used: 1967 - 1990

The face of the unit is marked:
'LEEDS & NORTHRUP'
'9838 GUARDED NANOVOLT DETECTOR'

No serial number is visible on the unit.

Dymo labels on the back of the unit are marked:
'BLACK/WHITE /P'
'RED GUARD'
'YELLOW GROUND'

The transformer is marked:
'FERGUSON'
TYPE TS115/30B'
PRi. 240V. 50Hz.'
'SEC. 115v. .26A. 30V.A.'
'0.35A. FUSE OUTPUT END'
'INPUT 240V'

2008/187/11

1965 - 1980

196 mm

313 mm

200 mm