Sawtooth generator circuit a

Posted on Mar 28, 2007

Application circuit is shown in a complementary sawtooth generator. In the figure, the horse is VT1 base current limiting resistor, the conduction time to prevent excessive bas

Sawtooth generator circuit a
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e current flows through the crystal tube VT1 base, R4 transistor VT2 collector leakage current bleeder resistor to ensure when VT2 end, VT1 reliable cutoff. One under normal circumstances, the power island EJ. When the power is Shu Yi cut turned from no charge in the capacitor C, so both ends of the electric voltage is zero (U0-0), then transistor VT2, the emitter potential is zero, the base potential is A potential point, so UA UE. Transistor VT2 off. VT1 base also granted without electricity surges, also in an off state. Power capacitor C is charged through the resistor Rs, with the increase in charging time, E point potential has also been on the rise. When the potential at the point E over A point potential, VT2 into the enlarged area, its collector current flows through the resistor R3 VT1 base, VT1 from the same cut-off and into the enlarged area, the collector current through the VT1 VT2 amplified again VT2 feedback to the base, so that the result of positive feedback, forcing VT1, VT2 are saturated. Capacitor C by saturated transistor VT1, VT2 discharge. With the increase of the discharge time, the voltage of the capacitor C continues to decrease. When the voltage drops to a certain point value E, if the parameters chosen, this time, the base current of transistor VT1 VT1 is not sufficient to maintain saturation, will turn off the circuit by making VT2 positive feedback form for off state, circuit into the second cycle. The output waveform is shown

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