Buzzer No. 19A is operated by a battery of two small secondary cells,
which are kept charged by a battery of five WK1 Leclanché cells connected
to them by a resistance of 100 ohms.
Buzzer No. 19B is powered by a 10 volt supply generally being mains charged.
| BACK | Home page | BT/GPO Telephones | A - Z Index | Glossary of Telecom Terminology | Quick Find | All Telephone Systems |