Blinking Lights! What is a Flasher Unit?
Tuesday, 5 March 2013 | AdrianR
Many modern-day indicators and hazard flasher units available on the market today can trigger a flashing circuit by pulse switching, old style flasher units (like the tin can type shown) work differently and contain a bimetallic strip. A bimetallic strip is made up of two different conductive metals riveted, welded or brazed together, so that when a current is passed through it (indicator light on), the two metals expand and contract at a different rate, the lower plate that expands the most creates a curling or bend in the strip that breaks the connection and allows a circuit to switch off (indicator light off), these type of strips are reliably timed when the correct current flow through the indicator lights is available. When a circuit is broken by the expansion bending of the bi-metallic strip, the current passing through the curled metal plate dissipates, causing the metals to contract back into place and the circuit to switch back on, which is displayed by the lamp switching 'on and off' or blinking, the process is repeated until the switch that instigated the circuit is switched off.
This blog post was created: 25th March 2013 and closed for comment 25th July 2015.