LED或闪光灯电路--LEDorLampFlasher

LED或闪光灯电路--LED or Lamp Flasher
  Minimum parts counting
  Designed for 3V battery operation
  
  Parts:
  R1_______33K1/4W Resistor
  R2,R3____47R1/4W Resistors
  C1_______10?F25V Electrolytic Capacitor
  D1,(D2)__LED(s) (Any type and color)
  Q1_____BC560 45V 100mA PNP Transistor
  Q2_____BC337 45V 800mA NPN Transistor
  Notes:
  Power supply can vary from 2 to 4.5V.
  Add D2 to obtain two LED alternate blinking.
  D1's on-time is shorter than off-time. The opposite regarding D2.
  You can also use D2 only, shorting D1.
  Don't change resistors' values.
  Flashing frequency can be varied changing C1 value from 2.2?F to 100?F and higher.
  This circuit is very efficient when driving a 3.2V lamp. In this case omit the LEDs and R3, connecting the lamp at Q2's collector and to positive supply, further reducing parts counting.