Electrical systems in products
Design & Technology · Key Stage 2 · The School
A circuit needs a loop
Cell, wires, component, back to the cell — a complete loop, or nothing happens. Add a SWITCH to break the loop on purpose. Everything electrical you own is this idea with more parts, and a break anywhere stops the whole thing.
Choosing a switch
A PUSH-TO-MAKE switch works only while held — a doorbell. A TOGGLE stays where you put it — a lamp. A REED switch closes near a magnet — a fridge door light or an alarm. Pick the switch by asking what the user's hand is actually doing.
Fault-finding in order
Work systematically rather than poking about: is the cell flat? Are the connections tight? Is the bulb blown — swap it? Is there a break in a wire? Test one thing at a time, and change only one thing before retesting. Random poking sometimes fixes it and teaches nothing.
A push-to-make switch works only while pressed — right for a doorbell. A toggle switch stays where you put it — right for a lamp. A reed switch closes when a magnet is near — right for a burglar alarm on a window. A tilt switch closes when the product is tipped — right for a warning buzzer on a wheelbarrow. Name what the user has to DO, and the switch chooses itself.