The PPM Model R9-1M-RC Decade Resistance Standard is a precision selectable resistance box.

DESCRIPTION

The PPM Model R9-1M-RC Decade Resistance Standard is an improved precision selectable resistance box with stability an order of magnitude better than standard units. Temperature coefficient on most ranges is less than 1 ppm/degree C. Inductance and capacitance are very low.

The Model R9-1M-RC Decade Resistance Standard covers nine decades of resistance. It is housed in a relay-rack mountable aluminum cabinet. The Model R9-1M-RC has a maximum settable resistance of 1,211,111.11 ohms. It employs precison switches for selecting resistance for the eight most significant decades, and has a single turn rheostat with 100 dial divisions for the least significant decade. All switches have 11 settings, from 0 to 10, except the most significant decade which has 12 settings from 0 to 11.

A front panel removable plate allows access to calibration trimming potentiometers for the eight most significant decades. Switches have quadruple-leaf brushes with solid silver contacts at all positions and are totally enclosed. Contact resistance is typically 0.0005 ohms. Switch detents have roller bearings to ensure a switch life in excess of one million revolutions. Insulation resistance is more than 10 teraohms. Thermal EMF is extremely low with silver contacts and silver alloy brushes. Capacitance between contacts or to ground is less than 1 picofarad.

Connections to the decade resistance box are made through four gold-plated low contact resistance five-way binding posts, which enables a "four-terminal" measurement. The binding posts are low thermal EMF type, with insulation resistance to case of greater than 10 teraohms. A separate binding post with a removable link is provided for a chassis ground connection.

SPECIFICATIONS

RESISTANCE RANGE

0.01 to 1,211,111.11 ohms.

Rheostat Resolution: 0.0001 ohms/division.

ACCURACY

20 ppm +/-1 milliohm at 23 degrees C.

TEMPERATURE COEFFICIENTS

100 ohms to 100K per step: +/-1 ppm/degree C.

10 ohms per step: +/-10 ppm/degree C.

1 ohm per step or less: +/-20 ppm/degree C.

Wiring and switches: +/- 50 micro-ohms/degree C.

POWER RATING

1.0 watt per step, 5.0 watts total, 2.0A max. current.

POWER COEFFICIENT (For Typical Duty Cycle)

100 ohms to 100K per step: +/- 0.1 ppm/mW/step.

10 ohms per step: +/-0.3 ppm/mW/step.

1 ohm per step: +/-0.4 ppm/mW/step.

0.1 and 0.01 ohms per step: +/-1.0 ppm/mW/step.

Wiring and switches: +/-50 micro-ohms/W total.

STABILITY

+/-(20 ppm + 0.5 milliohm) per year.

BREAKDOWN VOLTAGE

1500 volts peak to case.

ENVIRONMENTAL

Operating Temperature: 0 to +40 degrees C.

Storage Temperature: -55 to +60 degrees C.

Operating Humidity: 0-90% RH non-condensing.

PHYSICAL

Size: 7" H x 19" W x 9.5" D.

Weight: Under 14 pounds.

CALIBRATION

Traceable to NIST. Interval: 1 year. A certificate is

supplied showing value at each switch setting.

* Specifications subject to change without notice.