This circuit is from an old documentation, but perfectly current. In place of the battery, 2 or 4 small cells can be used.
August 2016 - It can be obtained from Mouser Electronics the battery protectors series bq7790x of...
We found this circuit in the ON Semiconductor Thyristor Manual although similar configuration can be found...
Published in 1988 in Hands-On Electronics, this circuit converts the 12 V of a battery into 120 V...