Car Bulb Power Flasher

Derived from the Two-wire Lamp Flasher design, hosted on RED Free Circuit Designs since 1999, this astonishingly simple circuit allows one or two powerful 12V 21W car bulbs to be driven in flashing mode by means of a power MosFet.
Devices of this kind are particularly suited for road, traffic and yard alerts and in all cases where mains supply is not available but a powerful flashing light is yet necessary.
Circuit Diagram:

Parts Description
R1 6.8K
R2 220K
R3 22K
C1 100uF-25V
C2 10u-25V
D1 1N4002
Q1 BC557
Q2 IRF530
LP1 12V-21W Car Filament Bulb (See Notes)
SW1 SPST Switch (3 Amp minimum)
  • Flashing frequency can be varied within a limited range by changing C1 value.
  • As high dc currents are involved, please use suitably sized cables for battery and bulb(s) connections.
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