Disposable camera flash capacitor charging limit?

[sinebar]

There is a tiny neon indicator in my disposable camera that flashes
when the camera is ready to take a picture. Does the neon indicator
limit the maximum voltage the photoflash capacitor can be charged? I
connected 2 AA batteries in series instead of the one it normally uses
but it didn't increase the amount of voltage the cap was charged to by
a significan amount. I was expecting 250-300 volts instead of the
normal 150 volts. I got about 175 volts but I had to let it charge
for quite a while to get that. It did charge up much faster though.

 

[Phil Allison]

"sinebar"

There is a tiny neon indicator in my disposable camera that flashes
when the camera is ready to take a picture. Does the neon indicator
limit the maximum voltage the photoflash capacitor can be charged?

** No.

connected 2 AA batteries in series instead of the one it normally uses
but it didn't increase the amount of voltage the cap was charged to by
a significan amount.

** The charging circuit has a simple voltage regulator.


.... Phil

 

[bw]

"sinebar" <sinebar3770@gmail.com> wrote in message
news:b7324ba9-0b77-4dc6-ba99-6cc2fb68c311@s18g2000vbe.googlegroups.com...

There is a tiny neon indicator in my disposable camera that flashes
when the camera is ready to take a picture. Does the neon indicator
limit the maximum voltage the photoflash capacitor can be charged? I
connected 2 AA batteries in series instead of the one it normally uses
but it didn't increase the amount of voltage the cap was charged to by
a significan amount. I was expecting 250-300 volts instead of the
normal 150 volts. I got about 175 volts but I had to let it charge
for quite a while to get that. It did charge up much faster though.

The cheap cameras found by the boxload at the thrift stores will almost
always have a charge cap rated at 330 volts.
I find that you will end up around 330 volts no matter how long you wait.
http://electronics.howstuffworks.com/camera-flash2.htm
Has a basic schematic that shows how the neon indicator works. It won't
affect the max charge.
The "rectifier diode" will prevent the neon lamp from draining the charge
after you turn off the circuit.
Sometimes the neon indicator is on the other side of the diode. In that case
if you turn off the charge circuit then the neon lamp will drain the charge
down to around 80 volts until the lamp goes out.

http://members.misty.com/don/donflash.html
Has done about anything you can to these xenon flash circuits.
Especially, read his safety link http://members.misty.com/don/xesafe.html

 

[sinebar]

On Feb 20, 7:45 pm, "bw" <bweg...@hotmail.com> wrote:

"sinebar" <sinebar3...@gmail.com> wrote in message

news:b7324ba9-0b77-4dc6-ba99-6cc2fb68c311@s18g2000vbe.googlegroups.com...

There is a tiny neon indicator in my disposable camera that flashes
when the camera is ready to take a picture.  Does the neon indicator
limit the maximum voltage the photoflash capacitor can be charged?  I
connected 2 AA batteries in series instead of the one it normally uses
but it didn't increase the amount of voltage the cap was charged to by
a significan amount.  I was expecting 250-300 volts instead of the
normal 150 volts.  I got about 175 volts but I had to let it charge
for quite a while to get that.  It did charge up much faster though.

The cheap cameras found by the boxload at the thrift stores will almost
always have a charge cap rated at 330 volts.
I find that you will end up around 330 volts no matter how long you wait.http://electronics.howstuffworks.com/camera-flash2.htm
Has a basic schematic that shows how the neon indicator works. It won't
affect the max charge.
The "rectifier diode" will prevent the neon lamp from draining the charge
after you turn off the circuit.
Sometimes the neon indicator is on the other side of the diode. In that case
if you turn off the charge circuit then the neon lamp will drain the charge
down to around 80 volts until the lamp goes out.

http://members.misty.com/don/donflash.html
Has done about anything you can to these xenon flash circuits.
Especially, read his safety linkhttp://members.misty.com/don/xesafe.html

Thanks for the links and the reply. I was measuring at the capacitor
leads.
Is that maybe giving me a wrong reading?

 

[Don Klipstein]

In <8461aa56-8949-4166-ad9b-96e84866ca95@g11g2000vbq.googlegroups.com>,
sinebar wrote:

On Feb 20, 7:45 pm, "bw" <bweg...@hotmail.com> wrote:
"sinebar" <sinebar3...@gmail.com> wrote in message

news:b7324ba9-0b77-4dc6-ba99-6cc2fb68c311@s18g2000vbe.googlegroups.com...

There is a tiny neon indicator in my disposable camera that flashes
when the camera is ready to take a picture.  Does the neon indicator
limit the maximum voltage the photoflash capacitor can be charged?  I
connected 2 AA batteries in series instead of the one it normally uses
but it didn't increase the amount of voltage the cap was charged to by
a significan amount.  I was expecting 250-300 volts instead of the
normal 150 volts.  I got about 175 volts but I had to let it charge
for quite a while to get that.  It did charge up much faster though.

The cheap cameras found by the boxload at the thrift stores will almost
always have a charge cap rated at 330 volts.
I find that you will end up around 330 volts no matter how long you wait.http://electronics.howstuffworks.com/camera-flash2.htm
Has a basic schematic that shows how the neon indicator works. It won't
affect the max charge.
The "rectifier diode" will prevent the neon lamp from draining the charge
after you turn off the circuit.
Sometimes the neon indicator is on the other side of the diode. In that
case if you turn off the charge circuit then the neon lamp will drain
the charge down to around 80 volts until the lamp goes out.

http://members.misty.com/don/donflash.html
Has done about anything you can to these xenon flash circuits.
Especially, read his safety link http://members.misty.com/don/xesafe.html

Thanks for the links and the reply. I was measuring at the capacitor
leads.
Is that maybe giving me a wrong reading?

Maybe the capacitor has not been used in years, and has gotten a
voltage-dependent leakage as a result. Aluminum electrolytic capacitors
are known to do that.

Often, they can be restored by exercising them. Apply charge to the cap
for several minutes, maybe half an hour. Maybe also discharge it every
couple or few minutes while doing this - preferably with the xenon
flashtube if it will work at the reduced voltage.

Also, be sure that your 1.5V AA cell is in good condition! There is
one 1-AA camera flash board that I tried with higher voltages, with
not-so-good results. At 2V, parts get uncomfortably hot and degrade in
operformance and produce a bit of smoky-burning odor. At 2.3V, it failed
with smoke production in mere seconds.

Another possibility, slight chance: Could your meter be loading down
the output? I like think that you need an unusually weak battery or an
unusually low impedance meter (or both) for that to happen, but there is a
test... Let the board run unmetered for 15 seconds after its output
voltage levels off, then put the meter back on. Is the voltage at that
time higher and decreasing towards the lower 175V one?

Now, yet another thing: I have known one 1-AA camera flash board to
have a neon lamp that does some regulating. Once the main capacitor
voltage reaches somewhere around 280 volts, the neon lamp turns on, and
adds significant loading to the capacitor. The neon lamp appears to me to
not achieve complete regulation; what I saw was partial regulation.
Also, that neon lamp had unusually high voltage across it while it was
glowing - around 260 volts IIRC. I suspect the neon was mixed with some
gas other than a "noble gas" to achieve that. This 1-AA camera flash
board was from Kodak "Max" cameras. I have seen 2 versions of this board
with minor differences between them. However, I am *disclaiming* that *all
versions* of the 1-AA flash board with high rate of usage in Kodak "Max"
cameras have this oddball-higher-voltage neon lamp.
--
- Don Klipstein (don@misty.com)

 

[sinebar]

On Feb 21, 2:42 pm, d...@manx.misty.com (Don Klipstein) wrote:

In <8461aa56-8949-4166-ad9b-96e84866c...@g11g2000vbq.googlegroups.com>,





sinebar wrote:
On Feb 20, 7:45 pm, "bw" <bweg...@hotmail.com> wrote:
"sinebar" <sinebar3...@gmail.com> wrote in message

news:b7324ba9-0b77-4dc6-ba99-6cc2fb68c311@s18g2000vbe.googlegroups.com....

There is a tiny neon indicator in my disposable camera that flashes
when the camera is ready to take a picture. Does the neon indicator
limit the maximum voltage the photoflash capacitor can be charged? I
connected 2 AA batteries in series instead of the one it normally uses
but it didn't increase the amount of voltage the cap was charged to by
a significan amount. I was expecting 250-300 volts instead of the
normal 150 volts. I got about 175 volts but I had to let it charge
for quite a while to get that. It did charge up much faster though.

The cheap cameras found by the boxload at the thrift stores will almost
always have a charge cap rated at 330 volts.
I find that you will end up around 330 volts no matter how long you wait.http://electronics.howstuffworks.com/camera-flash2.htm
Has a basic schematic that shows how the neon indicator works. It won't
affect the max charge.
The "rectifier diode" will prevent the neon lamp from draining the charge
after you turn off the circuit.
Sometimes the neon indicator is on the other side of the diode. In that
case if you turn off the charge circuit then the neon lamp will drain
the charge down to around 80 volts until the lamp goes out.

http://members.misty.com/don/donflash.html
Has done about anything you can to these xenon flash circuits.
Especially, read his safety linkhttp://members.misty.com/don/xesafe.html

Thanks for the links and the reply.  I was measuring at the capacitor
leads.
Is that maybe giving me a wrong reading?

  Maybe the capacitor has not been used in years, and has gotten a
voltage-dependent leakage as a result.  Aluminum electrolytic capacitors
are known to do that.

  Often, they can be restored by exercising them.  Apply charge to the cap
for several minutes, maybe half an hour.  Maybe also discharge it every
couple or few minutes while doing this - preferably with the xenon
flashtube if it will work at the reduced voltage.

  Also, be sure that your 1.5V AA cell is in good condition!  There is
one 1-AA camera flash board that I tried with higher voltages, with
not-so-good results.  At 2V, parts get uncomfortably hot and degrade in
operformance and produce a bit of smoky-burning odor.  At 2.3V, it failed
with smoke production in mere seconds.

  Another possibility, slight chance:  Could your meter be loading down
the output?  I like think that you need an unusually weak battery or an
unusually low impedance meter (or both) for that to happen, but there is a
test...  Let the board run unmetered for 15 seconds after its output
voltage levels off, then put the meter back on.  Is the voltage at that
time higher and decreasing towards the lower 175V one?

  Now, yet another thing:  I have known one 1-AA camera flash board to
have a neon lamp that does some regulating.  Once the main capacitor
voltage reaches somewhere around 280 volts, the neon lamp turns on, and
adds significant loading to the capacitor.  The neon lamp appears to me to
not achieve complete regulation; what I saw was partial regulation.
  Also, that neon lamp had unusually high voltage across it while it was
glowing - around 260 volts IIRC.  I suspect the neon was mixed with some
gas other than a "noble gas" to achieve that.  This 1-AA camera flash
board was from Kodak "Max" cameras.  I have seen 2 versions of this board
with minor differences between them.  However, I am *disclaiming* that *all
versions* of the 1-AA flash board with high rate of usage in Kodak "Max"
cameras have this oddball-higher-voltage neon lamp.
--
 - Don Klipstein (d...@misty.com)- Hide quoted text -

- Show quoted text -

Yeah I was thinking too that the neon tube was regulating. Never the
less, when I connected the
output of the flash unit to a trigger transformer that I plan on using
for my dye laser, I get a nice
fat spark and that's with just one battery powering the flash unit.
The input for the trigger transformer
is 240 volts so I figure the flash unit must be producing pretty close
to that. BTW the flash unit is out of
a small walgreen brand disposable camer. Its a tiny thing too.