GB895565A - Improvements in or relating to electrical monitoring circuits - Google Patents
Improvements in or relating to electrical monitoring circuitsInfo
- Publication number
- GB895565A GB895565A GB495559A GB495559A GB895565A GB 895565 A GB895565 A GB 895565A GB 495559 A GB495559 A GB 495559A GB 495559 A GB495559 A GB 495559A GB 895565 A GB895565 A GB 895565A
- Authority
- GB
- United Kingdom
- Prior art keywords
- transistor
- resistor
- current
- relay
- base
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
- H03K17/60—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being bipolar transistors
- H03K17/64—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being bipolar transistors having inductive loads
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/30—Modifications for providing a predetermined threshold before switching
Landscapes
- Emergency Protection Circuit Devices (AREA)
- Protection Of Static Devices (AREA)
Abstract
895,565. Protective arrangements. BRITISH TELECOMMUNICATIONS RESEARCH Ltd. Feb. 11, 1960 [Feb. 12, 1959], No. 4955/59. Class 38 (5). [Also in Group XL (c)] When the current I in a protected circuit goes above or below a predetermined range, it alters the bias on the base of a transistor TR1 to cause it to conduct or to cut-off and so produce the operation or release of a relay RA in the collector circuit of the transistor. In Fig. 2, resistor R6 is normally short-circuited by a transistor TR2 and the current I flowing to earth through a bias resistor R1 produces a potential drop across the resistor R1 in opposition to the potential due to the battery ES with the result that the transistor TR1 is cut-off and the relay is not energized. In the event of the current I falling below the lower limit of the predetermined range, the potential drop across the resistor R1 due to the current I is reduced and the base becomes sufficiently negative for the transistor to conduct. Should the current I exceed the upper limit, then the potential produced by the current across a resistor R4 is sufficient to cause the transistor TR2 to cease conducting and so remove the short-circuit from resistor R6. The base-emitter voltage of transistor TR1 then becomes negative so that transistor TR1 conducts and the relay RA is energized. Fig. 3 (not shown) illustrates a modified arrangement in which the transistor TR1 is normally conducting.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB495559A GB895565A (en) | 1959-02-12 | 1959-02-12 | Improvements in or relating to electrical monitoring circuits |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB495559A GB895565A (en) | 1959-02-12 | 1959-02-12 | Improvements in or relating to electrical monitoring circuits |
Publications (1)
Publication Number | Publication Date |
---|---|
GB895565A true GB895565A (en) | 1962-05-02 |
Family
ID=9787039
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB495559A Expired GB895565A (en) | 1959-02-12 | 1959-02-12 | Improvements in or relating to electrical monitoring circuits |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB895565A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2386078A1 (en) * | 1977-04-01 | 1978-10-27 | Yamato Scale Co Ltd | Fault indication circuit for seven segment displays - uses current sensing and logic comparator for each segment |
-
1959
- 1959-02-12 GB GB495559A patent/GB895565A/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2386078A1 (en) * | 1977-04-01 | 1978-10-27 | Yamato Scale Co Ltd | Fault indication circuit for seven segment displays - uses current sensing and logic comparator for each segment |
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