LED灯和脉冲发生器电路--LEDorLampPulser

LED或灯脉冲发生器电路--LED or Lamp Pulser
  Astonishing effect
  4.5V supply
  
  Parts:
  R1,R2___________4K71/4W Resistors
  R3_____________22K 1/4W Resistor
  R4______________2M21/4W Resistor (See Notes)
  R5_____________10K 1/4W Resistor
  R6_____________47R 1/4W Resistor (See Notes)
  C1______________1?F 63V Polyester Capacitor
  D1_____________5mm. Red LED (See Notes)
  IC1__________LM358Low Power Dual Op-amp
  Q1___________BC33745V 800mA NPN Transistor
  Circuit operation:
  This circuit operates a LED in pulsing mode, i.e. the LED goes from off state, lights up gradually, then dims gradually, etc.
  This operation mode is obtained by a triangular wave generator formed by two op-amps contained in a very cheap 8 pin DIL case IC. Q1 ensures current buffering, in order to obtain a better load drive.
  R4 & C1 are the timing components: using the values shown in the parts list, the total period is about 4 seconds.
  Notes:
  The most satisfying results are obtained adopting for R4 a value ranging from 220K to 4M7.
  Adopting for R4 a value below 220K, 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 Ohm.