There are three common types of flash relays used in trucks:
(1) Capacitive flasher
(2) Wing type flasher
(3) Electronic flasher
Capacitive flasher structure: composed of a relay and a capacitor. The iron core of the relay is wound with series coil and parallel coil, and the capacitor adopts high-capacity electrolytic capacitor (about 1500uF).
The working principle of a capacitive flasher: By utilizing the charging and discharging delay characteristics of the capacitor, the electromagnetic attraction generated by the two coils of the relay is sometimes added or subtracted, and the relay generates periodic switching actions, thereby causing the turn signal lights to flash.
The structure of a wing type flasher is composed of wings, thermal expansion strips, moving contacts, static contacts, and brackets. The wing is made of elastic steel and is usually tensioned into an arch shape by thermal expansion strips. The thermal expansion strip is made of alloy steel strip with a high expansion coefficient.
Operating principle of wing vane flasher: the wing vane flasher uses the thermal effect of current and the thermal expansion of the thermal expansion strip as the power to make the wing produce sudden action, connect and disconnect the contacts, and make the turn signal light flash.
Electronic flasher structure: composed of a switching circuit of a transistor, a capacitor, and a relay.
Working principle of electronic flasher: The electronic flasher utilizes the switching characteristics of the transistor and the charging and discharging delay characteristics of the capacitor to control the on and off of the relay coil, as well as the on and off contacts, to make the turn signal light flash. Electronic flashers are widely used in truck turn signal systems because of their reliable operation and long service life. Electronic flashers are divided into various forms such as contactless and contactless, integrated circuits, and transistors.