GB919427A - Improvements in or relating to alternating current generators - Google Patents
Improvements in or relating to alternating current generatorsInfo
- Publication number
- GB919427A GB919427A GB3292461A GB3292461A GB919427A GB 919427 A GB919427 A GB 919427A GB 3292461 A GB3292461 A GB 3292461A GB 3292461 A GB3292461 A GB 3292461A GB 919427 A GB919427 A GB 919427A
- Authority
- GB
- United Kingdom
- Prior art keywords
- cycle
- cycles
- mains
- contacts
- relays
- 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
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M19/00—Current supply arrangements for telephone systems
- H04M19/02—Current supply arrangements for telephone systems providing ringing current or supervisory tones, e.g. dialling tone or busy tone
- H04M19/04—Current supply arrangements for telephone systems providing ringing current or supervisory tones, e.g. dialling tone or busy tone the ringing-current being generated at the substations
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Devices For Supply Of Signal Current (AREA)
Abstract
919,427. Frequency changing. AUTOMATIC TELEPHONE & ELECTRIC CO. Ltd. Sept. 14, 1961, No. 32924/61. Class 38 (2). [Also in Group XXXIX] Alternate cycles of a 50-cycle mains supply are inverted to produce a waveform of 25 cycles suited for ringing current. As shown in Fig. 1, mains is connected to transformer winding WA. Output is taken from a centre-tapped winding WC, one cycle being delivered with contacts RA1 made, and the next cycle finding contacts RB1 made, and so on. The output waveform has two positive-going 50-Cycle halfcycles side-by-side followed by two negativegoing half-cycles and so on. Contacts RA1 and RB1 are controlled by a bi-stable circuit using transistors TX2 and TX3. Positive half-cycles from winding WB of the mains transformer cut off a normally bottomed transistor TX1 and the resulting 50-cycle square waveform is differentiated by capacitor C2. Rectifiers MR1, MR2 isolate the bi-stable circuit from negative inputs so that once in each mains cycle a positive spike switches the bi-stable circuit. Relays RA and RB are, therefore, operated alternately to reverse alternate mains cycles. The relays may be reed relays where the current required is small. A single relay with change-over contacts may be used. The 12 volts supply for the relay control circuit may be automatically disconnected when ringing is not in. demand.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB3292461A GB919427A (en) | 1961-09-14 | 1961-09-14 | Improvements in or relating to alternating current generators |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB3292461A GB919427A (en) | 1961-09-14 | 1961-09-14 | Improvements in or relating to alternating current generators |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB919427A true GB919427A (en) | 1963-02-27 |
Family
ID=10346021
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB3292461A Expired GB919427A (en) | 1961-09-14 | 1961-09-14 | Improvements in or relating to alternating current generators |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB919427A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2130849A (en) * | 1982-11-17 | 1984-06-06 | Lake Electronics Ltd | Apparatus for delivering a signal on a telephone line |
-
1961
- 1961-09-14 GB GB3292461A patent/GB919427A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2130849A (en) * | 1982-11-17 | 1984-06-06 | Lake Electronics Ltd | Apparatus for delivering a signal on a telephone line |
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