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close this bookCircuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut für Berufliche Entwicklung, 201 p.)
close this folder2. Bell Circuits
View the document(introduction...)
View the document2.1. Direct-current Bell
View the document2.2. Alternating-current Bell
View the document2.3. House Bell Installation
View the document2.4. Alarm Systems

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