On Thu, 09 Jan 2014 08:51:12 -0700, the renowned RobertMacy <robert.a.macy@gmail.com> wrote:>On Thu, 09 Jan 2014 08:20:51 -0700, Jan Panteltje ><pNaonStpealmtje@yahoo.com> wrote: > >> On a sunny day (Thu, 09 Jan 2014 08:06:53 -0700) it happened RobertMacy >> <robert.a.macy@gmail.com> wrote in <op.w9fdlrvg2cx0wh@ajm>: >>> ...snip... >>> I usually use series R and RF Bead, to get a 'well-rounded' response. >> >> [diode]C and L will resonate somewhere... >> > >NO!, not if done CORRECTLY. Also, RF Beads are NOT L, they're very lossy, >very low Q inductors.Be VERY careful with this assumption, as it's only true for relatively high frequencies. See below.>Again, DESIGN the solution. Don't 'throw' parts at the problem and wait >until it "worked this time."Amen to that. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
Series Resistor and TVS diode placement
Started by ●January 9, 2014
Reply by ●January 12, 20142014-01-12
Reply by ●January 12, 20142014-01-12
On Thu, 09 Jan 2014 15:20:51 GMT, Jan Panteltje <pNaonStpealmtje@yahoo.com> wrote:>On a sunny day (Thu, 09 Jan 2014 08:06:53 -0700) it happened RobertMacy ><robert.a.macy@gmail.com> wrote in <op.w9fdlrvg2cx0wh@ajm>: > >>On Thu, 09 Jan 2014 07:35:04 -0700, Jan Panteltje >><pNaonStpealmtje@yahoo.com> wrote: >> >>>> ..snip... >>> >>> And burn out the micro and diodes with any DC. >> >>Right. is that before or after the esd diode burns up? or when the series >>resistor burns up, what are these 0402's 1/64 w ?? > >The idea is that the _zener_ shorts. >For a short touch to for example a power line, >chances are things will still work. >Maybe you can use a fusible resistor, >as I mentioned it all depends on the power environment 24V, 110V, 230V. > > >>I usually use series R and RF Bead, to get a 'well-rounded' response. > >[diode]C and L will resonate somewhere...As a first line of defense against external RF intrusion (to meet the EU EMC directive) is to use a ferrite bead followed by a low inductance "UHF" chip capacitor to ground and use a PCB layout that inhibits any VHF/UHF/SHF energy from cell phones and wireless broadband to penetrate any deeper into the circuit from external leads. If you do not kill the RF energy as early as possible, it will be quite easily rectified by the protection diodes, which could cause wrong digital state to be read at a digital input.
Reply by ●January 13, 20142014-01-13
On Sun, 12 Jan 2014 10:25:27 -0700, Spehro Pefhany <speffSNIP@interlogdotyou.knowwhat> wrote:> On Thu, 09 Jan 2014 08:51:12 -0700, the renowned RobertMacy > <robert.a.macy@gmail.com> wrote: > >> On Thu, 09 Jan 2014 08:20:51 -0700, Jan Panteltje >> <pNaonStpealmtje@yahoo.com> wrote: >> >>> On a sunny day (Thu, 09 Jan 2014 08:06:53 -0700) it happened RobertMacy >>> <robert.a.macy@gmail.com> wrote in <op.w9fdlrvg2cx0wh@ajm>: >>>> ...snip... >>>> I usually use series R and RF Bead, to get a 'well-rounded' response. >>> >>> [diode]C and L will resonate somewhere... >>> >> >> NO!, not if done CORRECTLY. Also, RF Beads are NOT L, they're very >> lossy, >> very low Q inductors. > > Be VERY careful with this assumption, as it's only true for relatively > high frequencies. See below. > >> Again, DESIGN the solution. Don't 'throw' parts at the problem and wait >> until it "worked this time." > > Amen to that. > > > Best regards, > Spehro PefhanyNot an assumption, rather a sloppy statement. Thank you for the 'correction'. It is a good idea to carefully word statements for the 'soundbite' lurkers in order to prevent carrying away incorrect design rules. My simple statement was simply refuting the broad statement that the [diode]C and L will resonate somewhere. They resonate somewhere, but often, and luckily, the 'resonance' is up into the frequency where the RF bead has gone very lossy. There is also the matter of semantics between potential resonance AND actual resonant behaviour -- I had already 'assumed' the resonance was too high or was stomped on. Yes, a C and L will resonate somewhere, but its the designer's task to include these parameters and dampen any potential resonance with appropriate [and acceptable to the circuit's performance] R value. L Yes, RF beads do go through a 'spike' of 'inductance' but so does wire. My point is to account for ALL and DESIGN appropriately. That's why I said, "NO!, not if done CORRECTLY."
Reply by ●January 13, 20142014-01-13
Phil Hobbs wrote:> > On 1/11/2014 6:01 PM, Michael A. Terrell wrote: > > > > Phil Hobbs wrote: > >> > >> On 1/9/2014 9:16 AM, RobertMacy wrote: > >>> On Thu, 09 Jan 2014 05:28:55 -0700, Jan Panteltje > >>> <pNaonStpealmtje@yahoo.com> wrote: > >>> > >>>>>> ...snip... > >>>> I used zeners as it limits the voltage to both +zener voltage (use for > >>>> example a 5.6V zener for 5V micro), and -0.7V. > >>>> Or transzorbs. > >>>> > >>>> It also depends on speed required, and power environment, 24V, 110V, > >>>> 230V etc.. > >>>> > >>>> > >>> > >>> Jim, be careful of using zeners as circuit protection. They turn on > >>> EXTREMELY slowly and during that time can let a lot through. > >>> > >>> For grins, take two 5.6V zeners and put in series 'facing each other' as > >>> feedback on a high speed OpAmp. Then drive the thing and you won't get a > >>> square wave out, you'll get an extremely 'spikey' square wave out. We're > >>> talking audio frequencies, too. I've seen 20kHz spikes. > >> > >> I suspect that's the turn-on of the forward biased diode. Try the same > >> thing with a couple of 2N4007s in inverse parallel, and you'll see > >> spikes too. Zeners are usually fast. > >>> > >>> Do again with tranzorbs and you can really see the difference. > >>> > >>> Or, you can do what we used to do, slightly turn the zener on ahead of > >>> time, that helps. but takes a fast switching diode into the turned on > >>> zener. Today, too many parts, then, the only way. > > > > > > 2N4007? Don't you mean 1N4007? > > > > > Yes, of course. First digit equals number of leads minus one. ;)Someone had to ask. :) -- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge.
Reply by ●January 13, 20142014-01-13
josephkk wrote:> > IIRC in tubes the first number was about heater/filament voltage. See > the tubes in an old all American five receiver. Three 12 somethings a > 35W4 (rectifier) and a 50C5 (audio output pentode power tube).12AV6 (Detector, first audio amp) 12BA6 (IF amplifier) 12BE6 (Local Oscillator & mixer.) -- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge.
Reply by ●January 13, 20142014-01-13
On Mon, 13 Jan 2014 18:05:07 -0500, the renowned "Michael A. Terrell" <mike.terrell@earthlink.net> wrote:> >josephkk wrote: >> >> IIRC in tubes the first number was about heater/filament voltage. See >> the tubes in an old all American five receiver. Three 12 somethings a >> 35W4 (rectifier) and a 50C5 (audio output pentode power tube). > > >12AV6 (Detector, first audio amp) >12BA6 (IF amplifier) >12BE6 (Local Oscillator & mixer.)But..but 3JP1 is a tube and it has a 6.3VAC/600mA filament voltage. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
Reply by ●January 14, 20142014-01-14
"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> wrote in message news:te19d9dieuq221bebjg45r80rfdg83t3sk@4ax.com...> But..but 3JP1 is a tube and it has a 6.3VAC/600mA filament voltage.Of course, CRTs go by inches. :) Were there any CRTs with other-than-6.3V heaters -- or directly heated filaments for that matter? Tim -- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com
Reply by ●January 14, 20142014-01-14
On Mon, 13 Jan 2014 19:34:32 -0500, Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> wrote:>On Mon, 13 Jan 2014 18:05:07 -0500, the renowned "Michael A. Terrell" ><mike.terrell@earthlink.net> wrote: > >> >>josephkk wrote: >>>=20 >>> IIRC in tubes the first number was about heater/filament voltage. =See>>> the tubes in an old all American five receiver. Three 12 somethings =a>>> 35W4 (rectifier) and a 50C5 (audio output pentode power tube). >> >> >>12AV6 (Detector, first audio amp)=20 >>12BA6 (IF amplifier) >>12BE6 (Local Oscillator & mixer.) > >But..but 3JP1 is a tube and it has a 6.3VAC/600mA filament voltage.=20 > > >Best regards,=20 >Spehro PefhanyYes, there are some exception classes, your CRT being one as well as tuning indicator tubes and thyratrons. Larger transmitting tubes also usually do not follow the rule, e.g. my 4CX600J's. Nor do klystrons and traveling wave tubes. But at least the system tried to be somewhat descriptive. ?-)
Reply by ●January 14, 20142014-01-14
On 14.1.14 07:57, josephkk wrote:> On Mon, 13 Jan 2014 19:34:32 -0500, Spehro Pefhany > <speffSNIP@interlogDOTyou.knowwhat> wrote: > >> On Mon, 13 Jan 2014 18:05:07 -0500, the renowned "Michael A. Terrell" >> <mike.terrell@earthlink.net> wrote: >> >>> >>> josephkk wrote: >>>> >>>> IIRC in tubes the first number was about heater/filament voltage. See >>>> the tubes in an old all American five receiver. Three 12 somethings a >>>> 35W4 (rectifier) and a 50C5 (audio output pentode power tube). >>> >>> >>> 12AV6 (Detector, first audio amp) >>> 12BA6 (IF amplifier) >>> 12BE6 (Local Oscillator & mixer.) >> >> But..but 3JP1 is a tube and it has a 6.3VAC/600mA filament voltage. >> >> >> Best regards, >> Spehro Pefhany > > Yes, there are some exception classes, your CRT being one as well as > tuning indicator tubes and thyratrons. Larger transmitting tubes also > usually do not follow the rule, e.g. my 4CX600J's. Nor do klystrons and > traveling wave tubes. But at least the system tried to be somewhat > descriptive. > > ?-) >The larger transmitting tubes show the number of elements first: 3: triodes 4: tetrodes 5: pentodes A dash means an internal-anode glass tube, like 3-500Z A X means an external-anode tube, like 4X150A A CX means a ceramic-based external anode tube, like 4CX1000A The number at the end is the maximum anode dissipation in watts. The letter at the end in usually a version letter, with Z signifying a zero-bias Class B triode. -- Tauno Voipio
Reply by ●January 14, 20142014-01-14
On Mon, 13 Jan 2014 22:34:18 -0600, the renowned "Tim Williams" <tmoranwms@charter.net> wrote:>"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> wrote in message >news:te19d9dieuq221bebjg45r80rfdg83t3sk@4ax.com... >> But..but 3JP1 is a tube and it has a 6.3VAC/600mA filament voltage. > >Of course, CRTs go by inches. :) > >Were there any CRTs with other-than-6.3V heaters -- or directly heated >filaments for that matter? > >TimI don't know of any offhand, but I might suspect some of the miniature ones might. I took the cover off my ca. 1979 Unisonic XL-990 and found the CRT part number (Orion 60AB4) but didn't find a datasheet on the tube. (I guess the 60 is the diagonal measurement in mm, and it's a B&W P4 type phosphor). http://www.radiomuseum.org/r/northamftc_unisonic_xl_990.html It still functions after 35+ years, however, sadly, there are no more analog TV signals floating around the ether for it to receive. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
