Control008

                                          

LED or Lamp Pulser
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Schematic design of LED or Lamp Pulser
Part List :
Capacitors	Resistors
C1       =     1 μF / 63V Polyester Semiconductors IC1      = LM358 Q1      = BC337	R1,2  =   4K7 Ω ¼W R3     =   22K Ω ¼W R4     =   2M2 Ω ¼W R5     =    10K Ω ¼W R6     =      47 Ω ¼W Diodes D1     = LED red 5mm
Notes
This circuit operates a LED in pulsing mode, i.e. the LED goes from off state, lights up gradually, then dims gradually, etc. This circuit operates a LED in pulsing mode, i.e. the LED goes from off state, lights up gradually, then dims gradually, etc. TR4 & C1 are the timing components: using the values shown in the parts list, the total period is about 4 seconds.    The most satisfying results are obtained adopting for R4 a value ranging from 220KΩ to 4M7Ω.  Adopting for R4 a value below 220KΩ, the pulsing effect will be indistinguishable from a normal blinking effect.  The LED can be any type and color. You can use a filament lamp instead, provided its features are comprised in the range 3.2 to 6V, 200mA max. Using a lamp as a load, R6 must be omitted. Voltage supply range can be 4 to 6V: 4.5V is the best compromise. Don't supply the circuit with voltages exceeding 6V: it will work less good and Q1 could be damaged when a lamp was used as the load. At 6V supply, increase R6 value to 100 Ω.

Source : Electronics Lab