Power Unit; Circuit Description; Applications - Time Electronics 1010 User Manual

Time Electronics
1010 DC Voltage Calibrator
1.3

Power Unit

The 1010 is supplied with a internal mains/battery power unit. This can be configured when
ordered for either 115V or 230V AC, 50/60Hz. See section 2.7.
1.4

Circuit Description

The calibrator designed with a precision LTC 5V reference device which offers both
outstanding accuracy and temperature coefficient specifications. This provides the input to a
FET chopper amplifier system which operates in a feed-back stabilised mode, and has a
gain value determined by a set of precision metal film resistors which are selected by a 5
decade digital thumbwheel switch bank. The output voltage is variable from 0 to 9.9999
volts in 5 ranges. An output resistance of typically 0.05 ohms is maintained on the top three
ranges; the maximum output current that can be drawn on these ranges is automatically
limited to 25mA. This is designed to protect the electronic circuitry in the event of accidental
short circuit etc.
The lower ranges have an output resistance of 1 ohm and will supply current up to the short
circuit value (30mA), see output resistance in specifications. To ensure complete reliability of
the switch bank, each digit thumbwheel switch employs twin parallel gold plated contacts -
even if a contact fails the 1010 still functions correctly.
1.5

Applications

The uses of the instrument include the calibration applications of conventional voltage
potentiometers. A 1010 in these applications has the advantage of requiring no
standardisation and being able to supply much higher output currents without loss of
accuracy. Long term stability is inherent since standardisation is not required.
Other applications as a precision voltage source include calibration, linearity and gain
stability measurements, etc., on D.C. amplifiers, digital and electronic voltmeters,
transducers and as a variable low current power supply or backing-off voltage. The 10
ppm/HR stability and low noise levels are of particular interest when an extremely stable
voltage is required rather than a high accuracy calibration source.
1010 DC Voltage Calibrator
User Manual
v1.2
Page 6 of 19