Control009

                                          

2-Wire Lamp Flasher
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Schematic design of 2-wire lamp flasher
Part List :
Capacitors	Resistors
C1       =  220 μF / 25V Electrolytic C2       =    10 μF / 25V Electrolytic Others. LP1 = Filament Lamp: any type in the range 3-24V 10W max. SW1= On-Off switch B1   = VDC Source (3 - 24V suited to the lamp adopted)	R1    =    6K8 Ω ¼W R2    =  270K Ω ¼W R3    =    22K Ω ¼W Diodes D1    = 1N4002 (1A Diode) Semiconductors Q1  = BC557 Q2  = BD139
Notes
This circuit has been designed to provide that continuous light lamps already wired into a circuit, become flashing. Simply insert the circuit between existing lamp and negative supply. Especially suited for car or panel pilot lights, this device can drive lamps up to 10W.   Break lamp(s) to negative supply connection(s), then insert the circuit between existing lamp(s) connection(s) and negative supply (respecting polarities!).    C1 value can be varied from 100 to 1000 μF or higher, in order to change flashing frequency.  Although rather oversized, this circuit can also drive any LED, providing a suitable resistor is fitted in series with the light emitting device.  The resistor should be in the range 47Ω - 2K2Ω , depending on supply voltage.

Source : Electronics Lab