Extech Decade Operating Manual

Resistance Decade Box

Model 380400

Introduction

Congratulations on your purchase of the Extech 380400 Resistance Decade Box. This device offers 7
decades of resistance ranges from 1 to over 11MΩ (in 1Ω steps). Slide switches allow easy addition and
subtraction of resistance values. Binding posts (3) offer simple and secure connections. Careful use of
this decade box will provide years of reliable service.

Specifications

Resistance ranges 1 to 11,111,110Ω in 1Ω steps

Internal Resistance 0.3Ω

Power 0.3W Resistors

Connection Three (3) binding posts

Accuracy 1%

Operating conditions Temperature: 32 to 122

Dimensions/Weight 5.79 x 4.61 x 1.3" (14.7 x 11.7 x 3.3cm) / Approx. 0.69 lbs. (312g)

o

F (0 to 50oC) / Humidity: < 80%RH

User Guide

Operation

Binding Post Connections

The binding posts can be used for connections in several ways:

1. A banana plug can be inserted directly into the posts.

2. Bare wire can be threaded through the post after it has been unscrewed. Once the bare wire is threaded, tighten the posts as necessary.

3. Alligator clips can be used but use caution not to strip the post threads or plastic post housing.

The resistance output is available on the RED and the BLACK binding posts. The WHITE post is case ground and is typically not used. Connect the
positive lead of the device under test to the RED post. Connect the negative lead to the BLACK post. Use the WHITE grounding post only if the device
under test will be grounded to the 380400 case.

Range Selection

The 28 front panel switches are used to select the resistance that will be available on the RED and BLACK terminals. When a switch is set to the IN
position, the value printed above the switch is added to the total resistance available at the posts. When the switch is set to OUT it is excluded from
the total resistance. If all of the switches are set to OUT, the total output resistance is zero (+ 0.3Ω internal resistance – approx.).

For example, if the desired output value is 10.5KΩ, set the following switches to the IN position: 10K, 400Ω, and 100Ω.

Testing

This device can be used to verify the calibration integrity of MultiMeters, LCR meters, Calibrators, etc. Connect as described above in the Binding
Post Connection section. Set the resistance switches to output the desired resistance. Ensure that the voltage supplied by the device under test does
not overload the 0.3W internal resistor power rating. The device under test should read the value of resistance selected on the tester. If it does not,
the device under test may need calibration, adjustment, or repair.

Calibration and Repair Services

Extech offers complete repair and calibration services for all of the products we sell. For periodic calibration, NIST certification on most products
or repair of any Extech product, call customer service for details on services available. Extech recommends that calibration be performed on an
annual basis to ensure calibration integrity.

Warranty

EXTECH INSTRUMENTS CORPORATION warrants this instrument to be free of defects in parts and workmanship for one year from date of shipment (a six month limited warranty
applies on sensors and cables). If it should become necessary to return the instrument for service during or beyond the warranty period, contact the Customer Service Department
at [phone] ext. 210 for authorization or visit our website at www.extech.com (click on ‘Contact Extech’ and go to ‘Service Department’ to request an RA number). A Return
Authorization (RA) number must be issued before any product is returned to Extech. The sender is responsible for shipping charges, freight, insurance and proper packaging to
prevent damage in transit. This warranty does not apply to defects resulting from action of the user such as misuse, improper wiring, operation outside of specification, improper
maintenance or repair, or unauthorized modification. Extech specifically disclaims any implied warranties or merchantability or fitness for a specific purpose and will not be liable for
any direct, indirect, incidental or consequential damages. Extech's total liability is limited to repair or replacement of the product. The warranty set forth above is inclusive and no
other warranty, whether written or oral, is expressed or implied.

All rights reserved including the right of reproduction in whole or in part in any form.

Copyright © 2002 Extech Instruments Corporation.

Model 380400 Version 1.1 August 2002