 | Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut für Berufliche Entwicklung, 201 p.) |
 |  | 2. Bell Circuits |
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2.4. Alarm Systems
Circuit of an alarm system with
normally open contacts b1 test key, 1 glass panel
Circuit of an alarm system with
normally closed contacts b2 test key, 1 glass
panel
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