With either a Voltage Regulator or a Neon connected to a MOSFET gate, before the VR ignites, or the Neon ignites (There is a Higher voltage than the ignited voltage) . . .
Then Wham! The poor MOSFET may have been violated.
Please post a schematic of your circuit, MOSFET or other circuit, that uses a VR or neon.
Otherwise, we are all guessing, just like the blindfolded Archer trying to hit the target.
Then Wham! The poor MOSFET may have been violated.
Please post a schematic of your circuit, MOSFET or other circuit, that uses a VR or neon.
Otherwise, we are all guessing, just like the blindfolded Archer trying to hit the target.
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This is why MOS gates should be protected with zener diodes. The max Vgs of 20 V (typ., 30 V for some devices) has killed many MOSFETs.
Tom
If you chose to use a Neon lamp, be aware some contain traces of Kripton-85 or some other radioactive gas, and some do not.
Those which do not will not turn on in the dark. The Kr-85 provides ionizing energy to start the discharge.
In the early 80s when I worked inn the TI Industrial Controls division we used neon lamps on AC Input and Output modules. we experienced customer complaints about indicators not showing the on status of the channels. Upon investigation we found the lamps we used did not contain the trace gases needed to insure they turned on in the dark. This is less of a problem in well lighted areas. A neon lamp inside a dark chassis may not work.
Those which do not will not turn on in the dark. The Kr-85 provides ionizing energy to start the discharge.
In the early 80s when I worked inn the TI Industrial Controls division we used neon lamps on AC Input and Output modules. we experienced customer complaints about indicators not showing the on status of the channels. Upon investigation we found the lamps we used did not contain the trace gases needed to insure they turned on in the dark. This is less of a problem in well lighted areas. A neon lamp inside a dark chassis may not work.
I once bought four 85A2 voltage reference tubes from different brands and measured their start-up times in darkness. One from NEC started up in a few dozen microseconds, one from Philips and one from Pope in milliseconds, and one from Haltron in many seconds. Apparently there is quite a difference in the amount of radioactive primer between those 85A2's.
Stick with using gas regulator tubes that were made for that, or use Zeners.
I love the Shoulder tube OD3 that I have. I do not use it in a circuit anymore, but sometimes use it just for looks.
I never cared much for Neons in amplifiers.
Some use a Neon to "protect" a tube's Grid to Cathode voltage.
Example: A Neon that Fires at 90V, then ignites to 60V (what tube grid likes +60V, unless it is a high power class C RF tube, that is meant to take high transient grid currents.
Just use a silicon diode to keep the grid < +0.7V above the cathode.
Tektronix vacuum tube scopes used some Neons.
Guess what (*) was often replaced during the World Class Long Term Support (Tektronix used to give 12 Years support, and even supported longer than that).
Surprise: Neons were replaced. *
Are you worried about radioactive substances?
Then do the following:
1. Get rid of those surplus Military clocks, altimeters, etc. that use Radium activated dials.
2. Stop geting x-rays every year at the Dentist, Doctor, etc.
3. Fire Alarms with a radio-active substance.
All radiation that ionizes an atom in your body adds up (accumulates); and radioactive particles that are on/in your body are cumulative too.
In reality, all the above do not add up to enough radiation to be a problem, but your particular unusually large total amount of exposure may cause trouble.
Sleep at night, or you will have a different health problem . . . lack of sleep.
I love the Shoulder tube OD3 that I have. I do not use it in a circuit anymore, but sometimes use it just for looks.
I never cared much for Neons in amplifiers.
Some use a Neon to "protect" a tube's Grid to Cathode voltage.
Example: A Neon that Fires at 90V, then ignites to 60V (what tube grid likes +60V, unless it is a high power class C RF tube, that is meant to take high transient grid currents.
Just use a silicon diode to keep the grid < +0.7V above the cathode.
Tektronix vacuum tube scopes used some Neons.
Guess what (*) was often replaced during the World Class Long Term Support (Tektronix used to give 12 Years support, and even supported longer than that).
Surprise: Neons were replaced. *
Are you worried about radioactive substances?
Then do the following:
1. Get rid of those surplus Military clocks, altimeters, etc. that use Radium activated dials.
2. Stop geting x-rays every year at the Dentist, Doctor, etc.
3. Fire Alarms with a radio-active substance.
All radiation that ionizes an atom in your body adds up (accumulates); and radioactive particles that are on/in your body are cumulative too.
In reality, all the above do not add up to enough radiation to be a problem, but your particular unusually large total amount of exposure may cause trouble.
Sleep at night, or you will have a different health problem . . . lack of sleep.
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Maybe that had something to do with their respective dates of manufacture? The KR-85 half life is just under 11 years so presumeably the older they are the less they can be depended on to strike at nominal voltage.
I think the production date can only explain a part of the measured differences, unless Haltron used a primer with a very short half-life.
The random part of the ignition delay depends on how long it takes until an atom gets ionized and the resulting ion and/or electron get enough energy to start a chain reaction. I think that time should on average be inversely proportional to the amount of primer, as long as the effect of cosmic radiation and radioactive sources in the neighbourhood doesn't play much of a role. Looking at my measurements in darkness with 5 seconds on, 5 seconds off, the slowest tube ignited some 62621 times slower than the fastest. The time for the primer to decay that far can be quite long.
For example,
For tritium (common primer according to a book I read about glow discharge tubes):
12.32 years times the base-2 logarithm of 1.615 s/25.79 us is about 196.3 years
For krypton-85 (not mentioned in that book):
10.756 years times the base-2 logarithm of 1.615 s/25.79 us is about 171.4 years.
Hmm, I know nothing about it. Just interested.
My thinking is probably too simplistic. It runs: half gone in 11 years (10.756) , half again in another 11, half again in another 11,
so after 33 years there's only 12.5% of the original dose left. Decline by that much in other things would be considered significant.
All relationships and proportions are Linear; Unless they are Logarithmic or some other non-linear curves.
Try not to go Hyperbolic.
Sorry, I went off on a Tangent, instead of focusing on a Parabola.
There is a Half Ellipse in the US Capitol building (are you listening at one focal point, and hearing all that is said at the other focal point?).
Math is fun!
Try not to go Hyperbolic.
Sorry, I went off on a Tangent, instead of focusing on a Parabola.
There is a Half Ellipse in the US Capitol building (are you listening at one focal point, and hearing all that is said at the other focal point?).
Math is fun!