Couple of more things to add to this: 4) The +5V connection to R7 and T4 should be to +12V instead. Note=20 that the emitter of T1 can never be higher than whatever voltage is=20 on the emitter of T4 less one diode drop. There is NO downside to=20 having those two points at +12V rather than +5V. 5) This could be simplified significantly: change T1 to a PNP and=20 swap the E-C connections. Tie the bases together and to the=20 collector of T5. Note that R7 is tied to +12V, not +5v. Eliminate=20 T4 & T3 and all associated passives. This turns your charge pump into an emitter-follower circuit - its=20 not as efficient as having saturated switches but is much simpler and=20 safer - you can never have the situation of both T1 & T2 being=20 saturated at the same time. dwayne >Couple of things: > >1) the LEDs never turn off. They always see 12V applied to them via D2. > >2) T3 not necessary. Instead, connect the left side of R2 to T5c. > >3) I really RP's circuit. Why not give it a try? > >dwayne > > >At 04:29 PM 1/25/2011, Josh Koffman wrote: >>On Tue, Jan 25, 2011 at 5:59 PM, Josh Koffman wrote= : >> > Uh, clearly I wasn't thinking with my small transistors. New circuit >> > coming soon. >> >>Here's the latest! >> >>T3 switches the "Charge" transistor on, and keeps the cap charging >>while the PIC output is low. T5 acts as an inverter for T4, which >>keeps the "Flash" transistor off as long as the PIC output is low. >> >>Josh --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .