On a sunny day (Fri, 10 Jan 2014 00:05:50 -0800 (PST)) it happened Klaus Kragelund <klauskvik@hotmail.com> wrote in <dc83e714-b6c9-44d6-b7b1-e2085853577a@googlegroups.com>:>> I have used optos too, where spikes made other solutions impossible. >> >> > >They use optos for galvanic isolation, to combat common mode noise, since they handle signals in industrial environments with a >lot of ground bounce etc. > >For DM noise, use the tranzorb, resistor, diode, resistor combo > >Cheers > >Klausmm I have used them [optos] for incoming signals on several boards, it is simpler, more reliable, and allows interface spec set with one resistor. can easily be made mains proof too, do not forget reverse protection diode on the LED.
Series Resistor and TVS diode placement
Started by ●January 9, 2014
Reply by ●January 10, 20142014-01-10
Reply by ●January 10, 20142014-01-10
On Fri, 10 Jan 2014 09:00:58 GMT, Jan Panteltje <pNaonStpealmtje@yahoo.com> wrote:> >mm I have used them [optos] for incoming signals on several boards, >it is simpler, more reliable, and allows interface spec set with one resistor. >can easily be made mains proof too, do not forget reverse protection diode on the LED. >You can use the kind that have two back-to-back LEDs at the input. --sp
Reply by ●January 10, 20142014-01-10
On Fri, 10 Jan 2014 01:25:03 -0700, Jan Panteltje <pNaonStpealmtje@yahoo.com> wrote:> On a sunny day (Thu, 9 Jan 2014 22:29:53 -0800 (PST)) it happened mahen > <mahen.jnk@gmail.com> wrote in >> ...snip.... >> Thanks Jan. may be a dump Q. Series R2 b/w zener and connector already >> limiting the current into the pin, correct? Why series R1 >> again? > > If the zener limits to a bit[1] above supply, and bit[1] below ground, > then R1 limits the current into the on chip[2] diodes in the chip[2]. > [1] as in 'a little bit' > [2] as in 'silicon chip', better 'integrated circuit'. >YES! Built in to almost ALL IC's terminal accesses is a small protection device. Each protection device to each terminal keeps these chips alive even after poor handling during manufacturing. BUT! these devices are by necessity rather small and won't handle a lot of wattage, so putting a power limiting R between the terminal and the 'outside' world is always good insurance. Or in really robust designs the Engineer will put a whole [somewhat sacrificial] interface IC between the delicate uC/uP and the outside world.
Reply by ●January 11, 20142014-01-11
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? -- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge.
Reply by ●January 11, 20142014-01-11
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. ;) Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
Reply by ●January 11, 20142014-01-11
On Sat, 11 Jan 2014 19:21:24 -0500, the renowned Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> 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. ;) > >Cheers > >Phil HobbsSo why isn't an optcoupler 5N35? Maybe they don't count N/C leads. 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 12, 20142014-01-12
"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> wrote in message news:sbp3d9he2q2s15n53rqm018hsp3on605qp@4ax.com...> So why isn't an optcoupler 5N35? Maybe they don't count N/C leads.Probably the case. An old tradition: 6C4 is a triode (3) with a heater (3+1 = 4) in a 7-pin base. Though some broke this convention, like 6C5 (octal triode); tetrodes, beam tetrodes and true pentodes were sometimes 5 or 6, etc. The newer <pins-minus-one> <letter> <index> system featured tubes as well as semiconductors, so you have tubes like the 2E26 (beam tetrode). Although the 2 is obviously not the number of active pins. There are (were?) MOSFETs with substrate (back gate) in the 3N family. 2N7000 of course has shorted S-SS. And the fancier optos include 6N136 (photodiode tied to BJT/darlington), which really ought to be 5N by one-off logic. Was there any -N- series dual or multiple opto? 19N35 would seem to be a quad 4N35, which seems silly.. Tim -- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com
Reply by ●January 12, 20142014-01-12
On Sat, 11 Jan 2014 23:12:22 -0600, "Tim Williams" = <tmoranwms@charter.net> wrote:>"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> wrote in message=20 >news:sbp3d9he2q2s15n53rqm018hsp3on605qp@4ax.com... >> So why isn't an optcoupler 5N35? Maybe they don't count N/C leads. > >Probably the case. An old tradition: 6C4 is a triode (3) with a heater=20 >(3+1 =3D 4) in a 7-pin base. Though some broke this convention, like =6C5=20>(octal triode); tetrodes, beam tetrodes and true pentodes were sometimes=5=20>or 6, etc. > >The newer <pins-minus-one> <letter> <index> system featured tubes as =well=20>as semiconductors, so you have tubes like the 2E26 (beam tetrode).=20 >Although the 2 is obviously not the number of active pins. > >There are (were?) MOSFETs with substrate (back gate) in the 3N family.=20 >2N7000 of course has shorted S-SS. And the fancier optos include 6N136=20 >(photodiode tied to BJT/darlington), which really ought to be 5N by=20 >one-off logic. > >Was there any -N- series dual or multiple opto? 19N35 would seem to be =a=20>quad 4N35, which seems silly.. > >TimIIRC 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). ?-)
Reply by ●January 12, 20142014-01-12
Le Sat, 11 Jan 2014 19:21:24 -0500, Phil Hobbs a écrit:> 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. ;) >Does that count for 0nSemi too? -- Thanks, Fred.
Reply by ●January 12, 20142014-01-12
On Sat, 11 Jan 2014 23:12:22 -0600, the renowned "Tim Williams" <tmoranwms@charter.net> wrote:> >Was there any -N- series dual or multiple opto? 19N35 would seem to be a >quad 4N35, which seems silly..I don't think so. But the 6N136 has 8 leads with 2 NC (6 leads used) and it's not a 5Nxxx. Go figure. 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
