recharge within a preselected time well known electrical circuit analysis tools like spice are useful in this regard an consequence of introducing these additional charge resistors 222 and 226 is an increase in the current flowing in the zener diodes 218 and 220 this higher current results in a higher voltage drop across each avalanche transistor 202 and 204 this voltage drop must not rise above vcbo of the avalanche transistors or else the transistors will re trigger between pulses and fail sooner selecting zener diodes 218 and 220 with a lower reverse breakdown voltage keeps the voltage drop below vcbo high temperatures affect optical alignment of the pockels cell so waste heat is removed from an enclosure not shown surrounding the circuit by a fan motivated by a small 40 mm square 12 vdc brushless motor rated at 7 cfm the motor is driven by a small integrated circuit oscillator integral with the fan electro magnetic interference emi generated by the high voltage pulses generated by the circuit can interrupt normal operation of the fan causing it to run slower shielding the motor from the emi solves this problem when the pulse generator circuit 200 is configured to drive a pockels cell with 4 5 kv and 9 kv high.