🔍 Key Concepts
• Figure F is an emergency‑stop pushbutton; think about whether it is normally closed (NC) or normally open (NO) in a safety circuit.
• Look at the schematic symbols 1–8 and identify which show a pushbutton contact versus a toggle, rotary, or multi‑position switch.
• Emergency‑stop devices are usually drawn as an NC contact that opens when pressed; sometimes a dashed or mechanical linkage symbol shows that it is a maintained, lock‑in device.
💭 Think About
• First, decide what the electrical state of an emergency‑stop button should be when it is not pressed. How is power removed if a wire breaks?
• Next, among the symbols, which one clearly shows a momentary (pushbutton‑type) contact that is closed in the normal condition and opens when actuated?
• Also, do any of the symbols include a dashed line or extra mark indicating a mechanical latch or interlock, typical of an emergency‑stop mushroom?.
✅ Before You Answer
• Verify which symbol represents a pushbutton, not a toggle, selector, or multi‑pole rotary switch.
• Confirm that the contact shown is normally closed (NC) in the rest position and opens on operation, matching a fail‑safe E‑stop circuit.
• Double‑check that the chosen symbol could reasonably be labeled “EMERGENCY STOP” in a motor‑control or safety circuit diagram.