Single junction transistor time relay circuit three

Single junction transistor time relay circuit three

It uses a pulse charging
circuit, so the delay time can be very long, up
to tens of minutes. In the figure, the single-junction transistor VTi and other components
form the first-stage delay circuit, and the charging method of the capacitor Cl is
exponential change; VTz and other components form the second-stage delay circuit, and
the charging method of the capacitor Cz is the pulse charging method , and its terminal
voltage is Ladder changes. The total delay time of this circuit is equivalent to the product of the delay time of the two-stage relaxation oscillator.