The phase angle of the trigger pulse is derived by comparing the ramp voltage V2 at Pin 2 with the set value on the control input, Pin 3. The
slope of the ramp is determined by C3 and its chargingcurrent Iφ.
The charging current can be regulated, changed, altered using R8 at Pin 6.
The maximum phase angle, amax,(minimum current flow angle φmin) can also be adjusted by using R8 (see figure 5).
When the potential on Pin 2 reaches the set point level of Pin 3, a trigger pulse is generated whose pulse width, tp, is determined from the value of C3 (tp = 9 s/nF, seefigure 7). At the same time, a latch is set with the output pulse, as long as the automatic retriggering has not been activated, then no more pulses can be generated in that half cycle. Control input at Pin 3 (with respect to Pin 4) has an active range from –9 V to –2 V. When V3 = –9 V, then the phase angle is at its maximum amax i.e., the current flow angle is minimum. The minimum phase angle amin is set with V3 ≥ –1 V