referring to the figure , in parallel to input terminals 1 and 2 , there are connected a serial combination of a first charging diode 3 , a first charging capacitor 4 , a second charging capacitor 5 , a second charging diode 6 , and a first complementary pair of transistors 10 and 11 , the emitters of which being connected to the input terminals 1 , 2 , respectively , and the collectors of which being connected to a common point b of the first and second charging capacitors 4 and 5 . the bases of the first complementary pair of transistors 10 , 11 are connected , through respective feeding resistors 13 , 14 , to a common point a , to which the collectors of a second complementary pair of transistors 15 and 16 are respectively connected . the emitters of the second complementary pair of transistors 15 , 16 are respectively connected , through diode gates 7 and 8 and the charging diodes 3 , 6 , shunted by first and second smoothing condensers 9 and 12 , to the input terminals 1 , 2 . the bases of the second complementary pair of transistors 15 , 16 are mutually connected by means of a shunting charging resistor 17 , and by means of respective coupling condensers 18 and 19 , which in turn are connected to the common point b of the first and second charging capacitors 4 , 5 and the collectors of the first complementary pair of transistors 10 , 11 . after connecting the source of supply voltage to terminals 1 and 2 , one of the transistors 15 or 16 starts opening more quickly than the other . let us assume that it is transistor 15 . so , in the common point a of the collectors of transistors 15 and 16 , a positive voltage of the source appears . voltage drops in the semiconductor junctions may be neglected for making the case simpler . the positive voltage in the common point a causes the closing of the transistor 10 and the opening of the transistor 11 . in this way the common point b of the collectors of transistors 10 and 11 and the charging capacitors 4 and 5 is connected to the zero potential terminal 2 of the supply voltage , and the capacitor 4 is charged to the full voltage of the source through the charging diode 3 . as the coupling condensers 18 and 19 are also connected to the common point b , which is now connected to the zero potential terminal 2 , the coupling condenser 18 will be charged by the base - emitter path of the transistor 15 , and , through the charging resistor 17 , the coupling condenser 19 will be charged as well . the positive voltage across the bases of the transistors 15 and 16 causes a change of their conductivity . the transistor 15 closes while the transistor 16 opens and , in this way , connects the common point a of the collectors of the transistors 15 and 16 to the zero potential terminal 2 of the supply voltage source . this fact causes the opening of the transistor 10 and the closing of the transistor 11 . the common point b of the collectors of the transistors 10 and 11 and of the charging capacitors 4 and 5 has now the same potential as the positive terminal 1 of the source . as the charging capacitor 4 was charged in advance , the voltage between the positive end of capacitor 4 and the zero potential terminal 2 is doubled with respect to the voltage of the source . the smoothing condenser 9 is fed with this voltage through the diode gate 7 . simultaneously , the capacitor 5 is charged through the charging diode 6 and the coupling condenser 19 is discharged through the base - emitter path of the transistor 16 ; through the resistor 17 , there is discharged the coupling condenser 18 . the discharging of the coupling condensers 18 and 19 causes again a change of conductivity of the transistors . the transistors 15 and 11 open , the transistors 16 and 10 close . at the common point a , the potential is identical with the potential of the positive end of the smoothing condenser 9 , viz . it is higher than the voltage of the supply source . the common point b is connected again to the zero potential terminal 2 . the charging capacitor 4 is charged again through the diode 3 to the voltage of the source . the charging capacitor 5 is discharged through the diode gate 8 into the smoothing condenser 12 . simultaneously , the coupling condenser 18 is charged through the base - emitter path of transistor 15 and the coupling condenser 19 through the charging resistor 17 . the charging of these condensers causes again the change of conductivity of the transistors 15 and 16 and the process repeats in the described way . the smoothing condensers 9 and 12 are charged continuously up to the full voltage of the source . at the positive end of the smoothing condenser 9 , the voltage is doubled with respect to the zero potential terminal , and at the negative end of the smoothing condenser 12 , there is the same voltage , but of the opposite polarity than the voltage of the supply source . across the mentioned ends , the voltage is tripled with respect to the supply source . between the common points a and b , rectangular voltage pulses arise . if one marks the supply voltage u and if one neglects the voltage drops in the semiconductor junctions , then in case of conductivity of transistors 15 and 11 , at the common point a , a voltage of + 2u takes place , and at the common point b there is zero voltage . in case of conductivity of the transistors 16 and 10 , a voltage - u takes place at the common point a , and a voltage + u at the common point b . the change of these pulses is determined by the time constant of the coupling condensers 18 and 19 and the charging resistor 17 . the wiring may be carried out even with an opposite polarity of semiconductor elements , condensers and supply voltage . the invention may be applied for portable battery instruments , where one needs voltage pulses , the amplitude of which is a multiple of the feeding voltage of ordinary batteries , e . g . portable embodiments of instruments for electric acupuncture . although the invention is illustrated and described with reference to one preferred embodiment thereof , it is to be expressly understood that it is in no way limited to the disclosure of such a preferred embodiment , but it is capable of numerous modifications within the scope of the appended claims .
a source of pulses for the electronic suppression of pain is represented by a multivibrator wherein the amplitude of the output signal is double the value of the feeding voltage . the principle of the invention resides in a multivibrator provided with two sets of complementary pairs of transistors , one set of which works simultaneously as a switch and a feeder of voltage doublers . the multivibrator is fed by this increased voltage so that at the output , pulses of double amplitude arise , i . e . an amplitude four times greater than the value of the feeding voltage .