Car Relay Circuit: Switch, Coil and Window Motor
A dashboard switch on its own 5 A fuse sends 149 mA through a car relay coil; the relay switches 7.9 A to a window motor on a 15 A fuse.
Use this circuit in class: Car relay circuit: how an automotive relay switches a motor
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A car relay lets a small switch control a big load. The dashboard switch, on its own 5 A fuse, only carries the coil current, about 0.15 A here; the relay contact (terminals 30 and 87) carries the motor current, about 7.9 A, from the battery through a 15 A fuse.
Open and close the switch, change the coil resistance, the motor preset or its load, and watch both ammeters. Lock the motor once to see the 15 A fuse blow while the relay stays pulled in.
What's inside
- 1× Battery
- 1× Switch
- 1× Relay
- 2× Fuse
- 1× DC Motor
- Measured with Voltmeter/Ammeter
