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.