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Sunday, February 3, 2008

Suitable for alerting purposes Drives 12V Car bulbs

R1 6K8 1/4W Resistor

R2 220K 1/4W Resistor
R3 22K 1/4W Resistor
C1 100µF 25V Electrolytic Capacitor
C2 10µF 25V Electrolytic Capacitor
D1 1N4002 100V 1A Diode
Q1 BC557 45V 100mA PNP Transistor
Q2 IRF530 100V 14A N-Channel Hexfet
LP1 One 12V 21W Car Filament Bulb or two wired in parallel (See Notes)
SW1 SPST Switch (3 Amp minimum)

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.

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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