PPM, Inc. RX Series

DESCRIPTION

The PPM Model RX Series of decade resistor boxes is a line of precision resistance standards suitable for use as laboratory secondary standards. The RX series are available as three to seven decade units in various resistance values, ranging from 0.001 ohms per step to 1 megohm per step. All units are 3.5 inches high and 4 inches deep (excluding the dial knobs).

SWITCHES

Switches have solid-silver contacts at all positions. Thermal EMF is extremely low because of the silver contacts. All decades have 11 settings, from 0 through 10. Each decade will meet specified accuracy with switch operation life greater than 200,000 complete cycles (with 0 to 10 to 0 defined as one cycle).

BINDING POSTS

Binding posts are 5-way low-thermal type on standard 0.75 inch on-center spacing. A ground post is provided with a removable shorting bar to enable connection of the "low" terminal to case.

FREQUENCY CHARACTERISTICS

Resistance deviation from value at VDC < 0.5% at 1 KHz and < 5% at 10 KHz. Inductance is less than 0.8 microhenries (all decades set to zero). Capacitance is less than or equal to 15 pF per decade (any decade set to 10).

ZERO RESISTANCE

Zero resistance is less than 0.002 ohms per decade.

The Model Number code is as follows:

1. The digit following the letter "R" represents the number of decades.

2. The number after the hyphen represents the full-scale resistance in ohms. A "K" denotes kilohms.

3. A suffix "-RC" indicates the unit is 19" wide for relay-rack installation.

4. The absence of a suffix indicates a "bench" model, with width:

3 and 4 decade units: 12 inches

5, 6, and 7 decade units: 17 inches

Example: R7 -111.1111K-RC is a seven-decade rack-mounting unit with 111.1111 Kohms full scale.

SPECIFICATIONS

ACCURACY

+/-(0.01% of setting + 2 milliohms) at VDC and

23 +/-1 degrees C, referenced to zero resistance

setting.

POWER PER STEP

0.001 ohms per step: 0.025 watts

0.01 ohms per step: 0.16 watts

0.1 ohms per step: 0.25 watts

1 ohm per step: 0.5 watts

10 ohms per step: 0.5 watts

100 ohms per step: 0.5 watts

1 Kohms per step: 0.5 watts

10 Kohms per step: 0.5 watts

100 Kohms per step: 0.5 watts

1 Megohm per step: 0.5 watts

CURRENT PER DECADE

0.001 ohms per step: 5 Amps

0.01 ohms per step: 4 Amps

0.1 ohms per step: 1.6 Amps

1 ohm per step: 700 mA

10 ohms per step: 230 mA

100 ohms per step: 70 mA

1 Kohms per step: 23 mA

10 Kohms per step: 7 mA

100 Kohms per step: 2.3 mA

1 Megohm per step: 0.7 mA

MAXIMUM VOLTAGE

1 KV DC/peak AC, Hi or Lo terminal to case.

* Specifications subject to change without notice

User and Service Manual (.PDF Format)