Written by: Newton C. Braga

 
   This circuit is from an American publication of 1978. It can be assembled with modern transistors, since the MC1555 is simply the old Motorola version of the current 555. T1 can be a TIP41 and a T2 BD136. The transistor T3 may be a BC548. Resistors with non-standard values can be approximated. R5 is actually 180 ohm. The diodes can be 1N4002.