The detector works by using a JFET to detect the high impedance electric fields that are generated ... high voltage near the detector’s probe. A wire-wrapped resistor does double-duty serving ...

or the wire in the telephone fused. When not in use, the detector should be protected from dust and moisture. The crystals of the thermo-electric type of detector should be touched with the hands ...

Unscrew the device from the electrical box and pull it out. Insert the tester deep into the box and move it around. If it ...

Use an electrical tester to verify the power is off. Twist your old smoke detector to loosen it from its mounting plate.