I thought his initial incredulity around the firing cap highlighted just how much modern electronics and the energy density (and dischargeability) of modern tech has colored our expectations, even for people into older tech like the creator here. When he said the cube used no batteries in the camera, I immediately assumed that it was either going to be a firing cap like device, or he was about to talk about some obscure and forgotten "super-piezo" material. Small explosions of all sorts are the bread and butter of a lot of things from the mid-century. Your car is a rolling box of self contained explosions. Likewise any "small-engine" tool from chainsaws to weed-eaters to mowers. Children's toys like cap guns and poppers were full of them. "powder actuated tools" are another example. There's probably more, but I don't want to end up on a list googling for them
The first (and last) electric shock I ever got was taking apart a Canon Powershot A50 when I was a kid. Turns out flash capacitors produce a hell of a kick.... still get shivers thinking about that feeling, still have two dot scars on my index finger where it discharged. Pro tip: don't fuck with camera flashes. ;)
You're lucky, I've worked with vacuum tube electronics and being 'bitten' by electrolytic capacitors is an occupational hazard.
I'd guess I've been shocked hundreds if not thousands of times, one gets used to it. However, it's not the electrolytic capacitors that are charged to 250/350 volts that one worries about, if one works with high powered transmitters or similar equipment then their power supplies have capacitors that work at many thousands of volts which can remain charged after the equipment is switched off. Get across one of these and it's likely curtains, they're lethal.
Special precautions should be undertaken to discharge them and to ensure they remain discharged. Just discharging them isn't enough as a capacitor's dielectric 'relaxes' after being stressed by the voltage and its dimensions change which partially recharges the capacitor. To avoid a partial recharge its electrodes are short-circuited with wire while doing maintenance. This too can be hazardous, failure to remove the wire afterwards can lead to much damage.
I also got shocked by one of those capacitors once…
And then I proceeded to connect different wires to figure out how to recharge the capacitor and touch it with a screwdriver which proceeded to melt just so slightly that it got stuck to the lead.
I got bit by a big capacitor trying to take apart a disposable camera as a kid. I immediately threw it across the room. I was being very dumb, I heard it charge (I was prying with a screwdriver and shorted something that caused it to charge) but didn't register the danger.
The biggest jolt I ever got (also as a kid, I guess I must've learned eventually) was from a giant homemade capacitor I thought I had discharged fully after charging it with a van de Graaf generator. I fully grabbed both electrodes at the same time - very stupid, not as stupid as pulling the trigger on a gun you only think is unloaded but stupid in a pretty similar way. Must've created a circuit right through my heart. No idea what it's capacitance was, but it was made of I think about a foot of 2 inch PVC and aluminum foil, so not insubstantial.
But I don't have any scars, so I guess I got off easy!
I've used these flashbulbs but was never a fan of them because they were expensive, however they were the line of last resort back then as electronic flash units were very expensive.
The video shows that inside the flashbulbs you'll see a small blue dot. This was not discussed in the video nor was it mentioned in the comments—at least the ones I had time to read.
This dot is an important indicator in that it should always be blue, if it had turned pink then the bulb may not fire because the bulb's hermetic seal had been broken and air had gotten in (glass cracked, bad metal/glass seal on the firing electrodes). The ingress of air would dilute the oxygen atmosphere and likely oxidize the metal zirconium thread due to the presence of water vapor and the bulb wouldn't ignite or its light output would be suboptimal.
The blue dot would turn pink in the presence of air due to traces of water vapor in the air. It consisted of cobalt chloride which is blue in its dry state but turns pink when damp.
Some may recall cobalt chloride was used on ornamental weather indicators. As well as little figures of a man and woman popping in and out of a house to indicate dry and wet weather a large round dot of blotting paper soaked in cobalt chloride was used to do the same. In dry weather the dot would turn blue and wet it would turn pink.
Incidentally, when I was a naïve kid I asked my local pharmacist if he had any cobalt chloride so I could make my own indicators and [surprisingly] he actually had some and he put about 20gms in a small glass bottle and sold it to me for a few pence. He went to considerable effort to tell me that cobalt chloride was poisonous and he labeled the bottle with its contents and a big red poison label.
Oh how times have changed.
Edit: cobalt chloride also used to be widely used to indicate moisture in desiccants such as silica gel. Small amounts of blue cobalt chloride crystals would be added to dry gel. If they turned pink then the gel had become hydrated and needed to be replaced. Recently, it's been removed due to health concerns.
Interesting subject, for a change. Usually old camera stuff is just boring and bring up bad memories. We had color camera in 1950s, and the film was so expensive that using flash bulb everytime was good practice to ensure exposure was ok. Soviet-made bulbs were also cheap in Finland, but Agfa-film was developed only in West Germany and took a month.
We discovered the magicube bulbs were the perfect size to fit in the blow gun we had. It was quite impressive at night time when you hit a hard target. Or at least was at that age.
13 comments
[ 2.9 ms ] story [ 49.8 ms ] threadI'd guess I've been shocked hundreds if not thousands of times, one gets used to it. However, it's not the electrolytic capacitors that are charged to 250/350 volts that one worries about, if one works with high powered transmitters or similar equipment then their power supplies have capacitors that work at many thousands of volts which can remain charged after the equipment is switched off. Get across one of these and it's likely curtains, they're lethal.
Special precautions should be undertaken to discharge them and to ensure they remain discharged. Just discharging them isn't enough as a capacitor's dielectric 'relaxes' after being stressed by the voltage and its dimensions change which partially recharges the capacitor. To avoid a partial recharge its electrodes are short-circuited with wire while doing maintenance. This too can be hazardous, failure to remove the wire afterwards can lead to much damage.
Good memories.
The biggest jolt I ever got (also as a kid, I guess I must've learned eventually) was from a giant homemade capacitor I thought I had discharged fully after charging it with a van de Graaf generator. I fully grabbed both electrodes at the same time - very stupid, not as stupid as pulling the trigger on a gun you only think is unloaded but stupid in a pretty similar way. Must've created a circuit right through my heart. No idea what it's capacitance was, but it was made of I think about a foot of 2 inch PVC and aluminum foil, so not insubstantial.
But I don't have any scars, so I guess I got off easy!
The video shows that inside the flashbulbs you'll see a small blue dot. This was not discussed in the video nor was it mentioned in the comments—at least the ones I had time to read.
This dot is an important indicator in that it should always be blue, if it had turned pink then the bulb may not fire because the bulb's hermetic seal had been broken and air had gotten in (glass cracked, bad metal/glass seal on the firing electrodes). The ingress of air would dilute the oxygen atmosphere and likely oxidize the metal zirconium thread due to the presence of water vapor and the bulb wouldn't ignite or its light output would be suboptimal.
The blue dot would turn pink in the presence of air due to traces of water vapor in the air. It consisted of cobalt chloride which is blue in its dry state but turns pink when damp.
Some may recall cobalt chloride was used on ornamental weather indicators. As well as little figures of a man and woman popping in and out of a house to indicate dry and wet weather a large round dot of blotting paper soaked in cobalt chloride was used to do the same. In dry weather the dot would turn blue and wet it would turn pink.
Incidentally, when I was a naïve kid I asked my local pharmacist if he had any cobalt chloride so I could make my own indicators and [surprisingly] he actually had some and he put about 20gms in a small glass bottle and sold it to me for a few pence. He went to considerable effort to tell me that cobalt chloride was poisonous and he labeled the bottle with its contents and a big red poison label.
Oh how times have changed.
Edit: cobalt chloride also used to be widely used to indicate moisture in desiccants such as silica gel. Small amounts of blue cobalt chloride crystals would be added to dry gel. If they turned pink then the gel had become hydrated and needed to be replaced. Recently, it's been removed due to health concerns.
And now I know what was in the stem that set them off. Finally.