PPM Model R-120 Series

IET Labs suggests the HATS-LR in place of this unit...

DESCRIPTION

The Model R-120 series of resistance standards are a line of precision resistor boxes suitable for use as secondary laboratory standards of resistance. They are available from one ohm per step to 100 kilohms per step. All units have 12 resistors in series, with the capability of making four-terminal measurements of any individual resistor or any series string of resistors. These standards may also be used as precision voltage dividers, because of their high accuracy and their excellent temperature and long-term stability.

BINDING POSTS

26 low-thermal, 5-way binding posts provide two connections to each resistor terminal for use in four-terminal measurements. A binding post at each end of the R-120 is provided for connection to the metal case. Binding post spacing is standard 0.75 inch and 1.5 inch on centers, so that standard shorting bars may be used on each side of the unit. The shorting bars effectively connect ten resistors in parallel to provide a precision resistor with 1/10 of the value of an individual resistor. Thus each box may be used to provide precision resistor values covering two decades, from 1/10 of the nominal value per step, to 10 (or 12) times that nominal value. Nine resistors may be connected in series-parallel to yield the nominal step value, while averaging the errors of the nine resistors.

RESISTORS

Resistors are bulk metal foil type and hermetically sealed. Inductance and capacitance are considerably less than those parameters for equivalent wire-wound resistors. Temperature stability is better than 3 ppm per degree C., which is several times better than similar wire-wound resistors.

MODEL ORDER INFORMATION

R-120-1 for 1 ohm/step

R-120-10 for 10 ohms/step

R-120-100 for 100 ohms/step R-120-1K for 1K ohms/step

R-120-10K for 10K ohms/step

R-120-100K for 100K ohms/step

SPECIFICATIONS

ACCURACY

Initial: +/-20 ppm of nominal value,

at 23 degrees C., matched to 10 ppm.

Transfer: +/-1 ppm.

Calibration: +/-10 ppm.

STABILITY

Temperature: +/-3 ppm/degree C.

Long-Term: +/-20 ppm/year.

POWER RATING

Max. Power: 1 watt per resistor,

12 watts per 12 resistors.

Power Coeff.: +/-100 ppm/watt.

INSULATION

Leakage: 1,000,000 MS, terminals to case.

Breakdown: 1500 V peak, terminals to case.

PHYSICAL AND ENVIRONMENT

Size: 12" L x 3" H x 3.5" D.

Weight: Less than 5 pounds.

Environment: 0 to 55 degrees C.

* Specifications subject to change without notice.