1863: Difference between revisions

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|series=
|series=
|introduced=1970
|introduced=1970
|discontinued=current
|discontinued=the present day
|designers=
|designers=
|manuals=
|manuals=
* [[Media:GR 1863 and 1864 Instruction Manual 1863-0100-00.pdf|GR 1863 and 1864 Instruction Manual (1863-0100-00)]]
* [[Media:GR 1863 and 1864 Instruction Manual 1863-0100-00.pdf|GR 1863 and 1864 Instruction Manual (1863-0100-00)]]
* [[Media:GR 1863 and 1864 Instruction Manual 1863-0100-B 1973-03.pdf|GR 1863 and 1864 Instruction Manual (1863-0100-B, 1973)]]
* [[Media:GR 1863 and 1864 Instruction Manual 1863-0100-C 1974-08.pdf|GR 1863 and 1864 Instruction Manual (1863-0100-C, 1974)]] (readable schematics)
* [[Media:GR 1863 and 1864 Instruction Manual 1863-0100-C 1974-08.pdf|GR 1863 and 1864 Instruction Manual (1863-0100-C, 1974)]] (readable schematics)
* [https://www.ietlabs.com/pdf/Manuals/1863-64_im.pdf GR1863/1864 Instruction Manual, Aug 2018] @ IET Labs
* [https://www.ietlabs.com/pdf/Manuals/1863-64_im.pdf GR1863/1864 Instruction Manual, Aug 2018] @ IET Labs
* [[Media:GR-1863 and GR-1864 stitched schematics.pdf|GR-1863 and GR-1864 stitched schematics]]
{{Catalog History}}
{{Catalog History}}
}}
}}
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==Links==
==Links==
* The Model [[1864]] is similar but with a 200 TΩ top range, and test voltage variable from 10 V to 1090 V.
* The [[1864|Type 1864 Megohmmeter]] is similar but with a 200 TΩ top range, and test voltage variable from 10 V to 1090 V.


==Internals==
==Internals==

Latest revision as of 00:35, 22 April 2024

General Radio 1863
Megohmmeter
General Radio 1863 Megohmmeter

Available from 1970 to the present day

Manuals
Catalog History
 Document Year Page
Catalog U 1970 98
Catalog73 1973 182
Catalog78 1978 58
(All manuals in PDF format unless noted otherwise)

The GR Type 1863 Megohmmeter was introduced in Catalog U (1970). It is still available from IET Labs as of 2024.

Specifications

  • Test Voltage: 50, 100, 100, 250, or 500 V; 5 mA limit
  • Resistance Range: 50 kΩ 20 20 TΩ in 7 ranges

Links

  • The Type 1864 Megohmmeter is similar but with a 200 TΩ top range, and test voltage variable from 10 V to 1090 V.

Internals

The 1863 is solid-state except for the test voltage supply pass element, a 6AB4 (EC92) vacuum tube.

Current through the unknown is converted to a voltage using decade reference resistors from 2 kΩ to 200 MΩ. In the highest range (1 TΩ multiplier), feedback is used to multiply the effective reference resistance by a factor of 10.

A four-stage, FET-input amplifier drives an analog meter.

Photos