General Information

Serial #

4790

Part Number

1

Total Parts

1

AKA

N/A

Patents

N/A

General Description

metal casing & parts/ synthetic controls, meter casing, power cord & parts/ rubber? feet

Dimensions

Note: These reflect the general size for storage and are not necessarily representative of the object's true dimensions.

Length

26.0 cm

Width

18.1 cm

Height

14.8 cm

Thickness

N/A

Weight

N/A

Diameter

N/A

Volume

N/A

Lexicon

Group

Communications

Category

Service-test equipment

Sub-Category

N/A

Manufacturer

AKA

GENERAL RADIO

Country

United States of America

State/Province

Massachusetts

City

Concord

Context

Country

Canada

State/Province

Ontario

Period

1960s-1970s

Canada

A piece of equipment used at a Canadian manufacturing facility. The donor's father was Roland Ouellette who worked as an electronics technician at the CIP mill in Hawkesbury, Ontario. He was self taught in electronics but still received 4 patents for his inventions. Canadian Patents: # 925285 issued May 1, 1973; class 33-176; # 925286 issued May 1, 1973;  class 33-179; # 1222319 issued May 26, 1987;  class 354-29. United States Patent: #4,644,174 issued Feb 17, 1987.

Function

An instrument used in test circuits to either act as a high quality low power amplifier or as a null detector in potentiometer circuits where an unknown resistance or source voltage is tested against known values. This example was used in a pulp mill, in the electronics shop for maintenance purposes.

Technical

General Radio made some of the highest quality electronics test equipment in the 1950s-1970s and GR equipment was in the best equipped labs in universities, government and industry labs. The tuned amplifier/null detector was a fairly common types of apparatus found in many test labs be they government, university or corporate labs. Its function was essential to electronic apparatus testing and circuit design and testing. This type of instrument could be used in circuits operating between 20 C/S (Hz)-100 KC/s (KHz). This instrument first appeared in GR's 1961 catalogue & was still being made in the 1970s. Battery operated & portable, It could be used as a bridge detector at audio frequencies; an audio-pre-amplifier & general purpose, tunable, or broadband audio amplifier; an a-m detector for 0.5- to 500-MHz carrier frequencies (when used with a voltmeter detector); a sensitive audio wave analyser for approximate measurements (Ref. 1& 2).

Area Notes

Unknown

Details

Markings

black lettering on meter face reads "TUNED AMPLIFIER/ AND NULL DETECTOR/ TYPE 1232-A/ GENERAL RADIO COMPANY/ CONCORD MASSACHUSETTS U.S.A" with red "GR" logo/ white lettering on casing front for control functions & reading "SERIAL NO. 4790"

Missing

appears complete

Finish

textured grey painted casing/ grey & red controls/ plated controls/ grey meter casing with colourless transparent window/ black feet & power cord/ metallic parts

Decoration

curved metallic grey trim along side edges