Originally Posted by Geof  Many years ago I developed a chemical metering pump based on a flyback oscillator charging big caps which where then discharged through a solenoid to operate a diaphragm. This unit pumped 12 volts up to 65 volts. |
Geof,
20 years back (??) Walther had an ELECTRONIC target pistol. 9V battery, that would run an oscillator to produce 90+ volts across a cap, enough to drive a solenoid (firing pin). A friend was having issues with it, and I started going though possible "fault problems". One was if the battery was disconnected when the circuit was charged. Uh, not a good result. Walther did recall all the target pistols, but it was one of the more interesting ones.
Jack -- Charge Pumps are common on Integrated Circuits. One of the first ones was a RS232 converter that was connected to a +5V supply. The capacitors attached were used to "charge up" to 5V, then put on top of the 5V... giving almost 10V. Another one then would "flip the leads" allowing for a -10V. Hence the +5V was able to drive the +-9V requirement for RS232. I think MAX232 are still around today, but that was great as you didn't have to have a +-12V power supply, only the 5V and still provide RS232 voltage levels.
Tom