Two-wire flashing light

Circuit diagram:

Component:

R1______________6K8 1/4W resistor

R2____________270K 1/4W resistor

R3_____________22K 1/4W resistor

C1____________220µF 25V electrolytic capacitor

C2_____________10µF 25V electrolytic capacitor

D1___________1N4002 100V 1A Diode

Q1____________BC557 45V 100mA PNP transistor

Q2____________BD139 80V 1.5A NPN transistor

LP1___________ Existing incandescent bulb: any type in the 3-24V 10W maximum range.

SW1___________ Existing switch

B1____________Existing DC power supply: Any type within the 3-24V range, suitable for the lamp used.

Equipment application:

This circuit is designed to change a continuously lit light already connected to a circuit to a flashing light. Simply plug the circuit between the existing light and the negative power supply. Particularly suitable for automotive or panel indicator lights, this device can drive lights up to 10W.

Notice:

- Disconnect the lamp from the negative power supply, then insert the circuit between the existing lamp connection and the negative power supply (note the polarity!).

- The value of C1 can vary from 100 to 1000µF or higher to change the flicker frequency.

- Although somewhat oversized, this circuit can also drive any LED, provided that a suitable resistor is connected in series with the light-emitting device.

- The resistance should be in the range of 47 ohms to 2 kJ/m², depending on the power supply voltage.