220V发光灯电路--220VoltsFlashingLamps

220V发光灯电路--220 Volts Flashing Lamps
  Especially designed for Christmas tree lamps
  Replaces old thermally-activated switches
  
  Parts:
  R1___________100K 1/4W Resistor
  R2,R5__________1K 1/4W Resistors
  R3,R6________470R 1/4W Resistors
  R4____________12K 1/4W Resistor
  C1__________1000?F25V Electrolytic Capacitor
  D1-D4_______1N40071000V 1A Diodes
  D5__________P0102D400V 800mA SCR
  Q1___________BC32745V 800mA PNP Transistor
  Q2___________BC33745V 800mA NPN Transistor
  PL1__________Male Mains plug
  SK1__________Female Mains socket
   
  Device purpose:
  This circuit is intended as a reliable replacement to thermally-activated switches used for Christmas tree lamp-flashing. The device formed by Q1, Q2 and related resistors triggers the SCR. Timing is provided by R1,R2 & C1. To change flashing frequency don't modify R1 and R2 values: set C1 value from 100 to 2200?F instead.
  Best performances are obtained with C1=470 or 1000?F and R4=12K or 10K. Due to low consumption of normal 10 or 20 lamp series-loops intended for Christmas trees (60mA @ 220V typical for a 20 lamp series-loop), very small and cheap SCR devices can be used, e.g. C106D1 (400V 3.2A) or TICP106D (400V 2A), this last and the suggested P0102D devices having TO92 case.
  Important Note:
  For proper operation it's absolutely necessary to employ high Gate-sensitive SCRs.
  If you are unable to find these devices you can use Triacs instead. In this case the circuit operates also with relatively powerful devices. A recommended Triac type is the ubiquitous TIC206M (600V 4A) but many others can work.
  Note that in spite of the Triac, diode bridge D1-D4 is in any case necessary.
  This circuit was awarded with publication in ELECTRONICS WORLD "Circuit Ideas", June 2000 issue, page 458.