"DaveC" <not@home.cow> wrote in message news:0001HW.1B9BFB3100248A5811E4F83CF@news.eternal-september.org...> Dead. Other with identical markings measure as NPN. What else to determine > from measurements?Find a modest to high voltage supply, add a large series resistor (10k-100k?), and measure the reverse breakdown. Wire it as a common emitter amplifier, not really to amplify but just to check bias. Play with base resistors until you get the edge of saturation for some collector current. Then double the collector current and do it again. That'll more or less let you plot hFE(Ic). Where it drops by half or so is near Ic(max). Now you know Vebo, Vcbo, hFE and Ic(max). Vebo is generally less than 5V for RF parts, so you'll likely have a high fT in that case. You can set it up with a square wave input to measure t_r, t_f, t_stg etc. if you like. Tim -- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com
Transistor identification?
Started by ●September 5, 2015
Reply by ●September 6, 20152015-09-06
Reply by ●September 7, 20152015-09-07
On 09/05/2015 11:46 PM, N_Cook wrote:> On 05/09/2015 21:28, DaveC wrote: >> Help with identifying a TO-92 transistor?(at least I think it’s a >> transistor…) >> >> Pretty vanilla-looking with National Semi logo. Marked: >> >> NS 444 >> ST >> 13903 >> >> (The “NS” is the logo.) >> >> Not enough 4’s to make up a standard 2N number, and 13903 looks like a >> date >> code? >> >> Ideas? >> >> Thanks, >> > > Or maker ST and date code for 1994 or 2004 or whatever goes with NS as > plant/batch code for a particular decadeHis next post gave a link to a photo of the transistor. Sure looks like National Semiconductor to me. My guess is the date is from the 90s based on the edge of the capacitor shown in the same photo - makes the date 1994 and 44th week. It will be Silicon then and Ted's recent post in this thread gave a very good explanation on how to identify its parameters using an identical transistor. The OP could tell us if there are other transistors using the 13903, but a different code beside the NS symbol - that would pretty much show that three digit number is the date code if it is something like 4xx, 3xx, or 5xx which would be a reasonable spread for date codes for a special run. John :-#)# -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out."
Reply by ●September 7, 20152015-09-07
On Mon, 7 Sep 2015 13:29:29 -0700, John Robertson <spam@flippers.com> Gave us:>John :-#)# >-- >(Please post followups or tech inquiries to the USENET newsgroup) >John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 >(604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) > www.flippers.com > "Old pinballers never die, they just flip out."Ever use "MAME"?
Reply by ●September 17, 20152015-09-17
"DaveC" <not@home.cow> wrote in message news:0001HW.1B9BFB3100248A5811E4F83CF@news.eternal-september.org...>> How's it measure? >> >> (Or if it's dead, is there another one probably working that you can >> test?) >> >> Tim > > Dead. Other with identical markings measure as NPN. What else to determine > from measurements?You can usually distinguish the B/E junction because it will zener somewhere around 5 - 8V ish. You need to keep the test current pretty low - you can get ultra-efficient LEDs that give a useable indication at only 2mA. Hook one of those up with an A23 12V keyfob battery and a current limiting resistor.
Reply by ●September 17, 20152015-09-17
On Thu, 17 Sep 2015 20:16:17 +0100, "Ian Field" <gangprobing.alien@ntlworld.com> wrote:> >"DaveC" <not@home.cow> wrote in message >news:0001HW.1B9BFB3100248A5811E4F83CF@news.eternal-september.org... >>> How's it measure? >>> >>> (Or if it's dead, is there another one probably working that you can >>> test?) >>> >>> Tim >> >> Dead. Other with identical markings measure as NPN. What else to determine >> from measurements? > >You can usually distinguish the B/E junction because it will zener somewhere >around 5 - 8V ish. > >You need to keep the test current pretty low - you can get ultra-efficient >LEDs that give a useable indication at only 2mA. Hook one of those up with >an A23 12V keyfob battery and a current limiting resistor.InGaN (true) green LEDs are quite bright at only 1mA. They can be seen at much less than that.
Reply by ●September 18, 20152015-09-18
On 2015-09-17 21:16, Ian Field wrote:> > "DaveC" <not@home.cow> wrote in message > news:0001HW.1B9BFB3100248A5811E4F83CF@news.eternal-september.org... >>> How's it measure? >>> >>> (Or if it's dead, is there another one probably working that you can >>> test?) >>> >>> Tim >> >> Dead. Other with identical markings measure as NPN. What else to >> determine >> from measurements? > > You can usually distinguish the B/E junction because it will zener > somewhere around 5 - 8V ish. > [...]You do that with low noise transistors and they'll be useless. Jeroen Belleman
Reply by ●September 18, 20152015-09-18
On 09/17/2015 08:05 PM, krw wrote:> On Thu, 17 Sep 2015 20:16:17 +0100, "Ian Field" > <gangprobing.alien@ntlworld.com> wrote: > >> >> "DaveC" <not@home.cow> wrote in message >> news:0001HW.1B9BFB3100248A5811E4F83CF@news.eternal-september.org... >>>> How's it measure? >>>> >>>> (Or if it's dead, is there another one probably working that you can >>>> test?) >>>> >>>> Tim >>> >>> Dead. Other with identical markings measure as NPN. What else to determine >>> from measurements? >> >> You can usually distinguish the B/E junction because it will zener somewhere >> around 5 - 8V ish. >> >> You need to keep the test current pretty low - you can get ultra-efficient >> LEDs that give a useable indication at only 2mA. Hook one of those up with >> an A23 12V keyfob battery and a current limiting resistor. > > InGaN (true) green LEDs are quite bright at only 1mA. They can be > seen at much less than that. >An ordinary 4-3/4 digit DVM on the lowest volts range (400 mV usually) makes a poor man's picoammeter. The 10 megohm ones read 1 LSB (0.01 mV) for 1 pA. Some of the older ones, where the lowest range doesn't have the 10M resistor in parallel, can be much more sensitive than that. You aren't going to hurt a transistor with a nanoamp of reverse base current, and the measurement is pretty simple. 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
