A New Magnetic-Coupled Monostable Multivibrator with Variable an Wide Pulsewidt

It is well known that magnetic-coupled monostable multivibrators have isolated and high-power outputs. These multivibrators which have been presented so far employ the operation of the major hysteresis loop. In these multivibrators, however, the output pulsewidth cannot be controlled over wide ranges and is severely influenced by variations in the source voltage. These problems can be solved by using the operation of the minor hysteresis loop and an R-C network to determine the pulsewidth. In this circuit, the output pulsewidth and the magnitude of output voltage can be controlled independently. The pulsewidth is expressed as T0 = CR In 2 until the magnetic core is saturated and easily adjusted by making either the resistor or capacitor variable. The magnitude of output voltage can be varied by the winding ratio and by the source voltage. A maximum-to-minimum pulsewidth ratio can be extended to about 1000. This value is 100 greater than that of the circuit employing the operation of the major hysteresis loop. The linearity error of the R-T0 characteristics is less than ± 0.1 percent. Its load characteristics are much better than those of conventional transistor multivibrators. The stability for the change of the source voltage is reduced to 0.06 percent/V over the range 4 to 12 V.