yes, you can do like this. I suggest , connect a resistor of 470 kohm or so across the pins of the capacitor, each of them. This is for safety .Related question: now that I have 3 different capacitors with different capacities (and therefore brightnesses), I'm considering making the flash "adjustable" by wiring all three capacitors into the circuit, with the positive ends running through 3 points on a rotary switch (sorry if I'm not using the correct terms). So basically, on any of the 3 positions, only 1 capacitor would be completing the circuit, while the other two would be open, so I can turn the dial to select among the 3 capacitors. Does anyone have any thoughts on why that would be a bad idea?
Some flash units switch in an additional capacitor to increase the power. Many increase the voltage to increase the power. And in all instances, the recharge speed is limited by the capability of the charging power supply. The reality is that the ony place the flash energy comes from is the power source that charges the capacitor. And the only way to charge a capacitor faster is to supply more current.Thanks everyone for the suggestions, I will try some of these and see how I go. A couple of follow ups.
First, I should have clarified at the start that the end product needs to fit in a small underwater housing, so size is a big limiting factor (thus no D cells and I can't hook up to an external power source).
Second, the information about the limitations of system are useful, but does anyone know how higher-quality flashes achieve faster recycle times? I have another flash that also runs on 2AA, but on its lower settings (it is adjustable) the recycle time is well under 1 second, and even on its highest setting (much brighter than the ones I am modifying) it recycles in under 3 seconds. That one is more expensive, so I don't want to dismantle it for this project, but I opened it up once to have a look, and it also uses a single 330V capacitor, but it is much larger (several hundred microfarads [I forget the exact value]), which brings me back to wondering how the adjustable flash circuit works, and what is allowing it to recycle so quickly while using the exact same batteries.
thanks again
More current by using higher input voltage which, may increase the maximum charge and, net-net, the same amount of charging time if there is no on-board voltage reference as many of these very cheap flashes don't have. .Some flash units switch in an additional capacitor to increase the power. Many increase the voltage to increase the power. And in all instances, the recharge speed is limited by the capability of the charging power supply. The reality is that the ony place the flash energy comes from is the power source that charges the capacitor. And the only way to charge a capacitor faster is to supply more current.
A hot capacitor is not a good sign, indeed. Get a multimeter and check the voltageThanks everyone, this thread has been super useful.
Another follow up, how concerned should I be if the capacitors get a bit hot when I leave the flash on for a while with the 3.7V battery? I'm assuming that's not a good sign
Well, if you described the "should-be" case, and he is observing something else, then he might have a problem, right?It is the charge/discharge that makes the heat, not the staying charged. So leaving it on, not flashing, should not overheat the capacitors.
If the higher voltage battery is causing the cap to charge to a proportionally higher voltage, then you may be exceeding the rated voltage of the capacitor. Or your faster charge/discharge cycles may be causing resistive heating in the charge and discharge events. Replacing with a lower ESR rated capacitor could reduce the heating.I'm assuming that's not a good sign
Some designs have two primary windings to allow the designer to connect them in parallel dorm more current or series for higher voltage (e.g. allow a 115vAC input using two connected in series) or 230vAC (two input windings connected in parallel - or using only one of the two primarily coils).More specifically, I'm struggling to understand the number of pins on transformers. The one on the flash has 5 (3 on the primary side and 2 on the secondary). Most of the ones I'm seeing online are symmetrical (same number on both sides) and many have more than 3 pins per side. Can anyone explain?
by Duane Benson
by Aaron Carman
by Jake Hertz