b-bassett
Newly Enlightened
hi all
I'm hoping someone can help with this problem
a year or so ago a built a quad xre , mag based, diving torch, with a 6 x D cell 6000MaH Nimh umbilical battery pack
i used a KD 2.8 p7 driver with the LED's in 2p2s and switched the power using a piezo momentary switch and a small latching circuit.
all worked well although i didn't seem to be getting full output (due to a 0.7V drop in the latching circuit.
and then i flooded it
so.. i rebuilt with better seals and an extra battery
now iv got problems...
when fully charged i cannot get high or medium power, all i get is a quick flash then the light goes out. low power works fine however.
removing the extra battery solves this problem, as does letting them partially drain down.
testing with a bench PS replicates the fault under certain conditions
with an input voltage below 8.3V all works fine.
increasing above 8.3V and the problem arises, unless i also increase the input current above 80mA @ 8.4V then continue to increase until i get to 3A @ 12V (PS max 3A)
the only faults i can think of are:
a) the input voltage is too high for the components (although both the driver and latch circuit are designed for up to 12V)
b) the initial rush of current does not increase rapidly enough causing the circuit to de-latch
c) the extra voltage is causing the switch to bounce ( although why would increasing the current solve this?)
I'm hoping someone here can help me as i would like to have my torch running at full power when down in a wreck at 50M
here's the circuit I'm using
and here's the original ''Relay Toggle Circuit Using a 555 Timer''
http://www.bowdenshobbycircuits.info/page9.htm#555-T.gif
teh only changes i made were a darlington pair transistor for higher current capabilities, i omitted the resistor+capacitor filter combo and swapped the relay for an LED driver
I'm hoping someone can help with this problem
a year or so ago a built a quad xre , mag based, diving torch, with a 6 x D cell 6000MaH Nimh umbilical battery pack
i used a KD 2.8 p7 driver with the LED's in 2p2s and switched the power using a piezo momentary switch and a small latching circuit.
all worked well although i didn't seem to be getting full output (due to a 0.7V drop in the latching circuit.
and then i flooded it
so.. i rebuilt with better seals and an extra battery
now iv got problems...
when fully charged i cannot get high or medium power, all i get is a quick flash then the light goes out. low power works fine however.
removing the extra battery solves this problem, as does letting them partially drain down.
testing with a bench PS replicates the fault under certain conditions
with an input voltage below 8.3V all works fine.
increasing above 8.3V and the problem arises, unless i also increase the input current above 80mA @ 8.4V then continue to increase until i get to 3A @ 12V (PS max 3A)
the only faults i can think of are:
a) the input voltage is too high for the components (although both the driver and latch circuit are designed for up to 12V)
b) the initial rush of current does not increase rapidly enough causing the circuit to de-latch
c) the extra voltage is causing the switch to bounce ( although why would increasing the current solve this?)
I'm hoping someone here can help me as i would like to have my torch running at full power when down in a wreck at 50M
here's the circuit I'm using
and here's the original ''Relay Toggle Circuit Using a 555 Timer''
http://www.bowdenshobbycircuits.info/page9.htm#555-T.gif
teh only changes i made were a darlington pair transistor for higher current capabilities, i omitted the resistor+capacitor filter combo and swapped the relay for an LED driver
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