Electronic flasher control circuit - with cascade transistor to monitor current and detect lamp failure

摘要

The electronic flasher circuit comprises an astable switching circuit of a single transistor and a switching relay. The frequency of the flasher is determined by an RC circuit while the current through the lamps is monitored by a cascade circuit of two transistors. This provides an instant current monitor and eliminates the dead period in conventional relay monitors, which can lead to the transistor 'fluttering'. If a bulb should fail, the current in the remaining bulb is reduced and the frequency of flashing increases to provide a warning for the driver.