Zener kinda turns on

turns on and if you power it up with 12V the 5V LED goes off and the 12V indicator goes on.

until I provide it a voltage drop of 5.6V, and since it's in series with some other stuff (resistors and an LED) I thought it would definitely be off at 5V, but it's on just enough to turn on my FET M1 and not let my D4 LED light up... I'm basically measuring a little over 1V at the gate.

maybe, but why is D1 turning on at all? Is it leakage current that's causing this circuit not to work at 5V? D3 the 12V LED is definitely off at a 5V supply (as it should be) and the circuit works at 12V... but not at 5V...

One final pass...

then back to real work >:-} ...Jim Thompson

turns on and if you power it up with 12V the 5V LED goes off and the 12V indicator goes on.

until I provide it a voltage drop of 5.6V, and since it's in series with some other stuff (resistors and an LED) I thought it would definitely be off at 5V, but it's on just enough to turn on my FET M1 and not let my D4 LED light up... I'm basically measuring a little over 1V at the gate.

maybe, but why is D1 turning on at all? Is it leakage current that's causing this circuit not to work at 5V? D3 the 12V LED is definitely off at a 5V supply (as it should be) and the circuit works at 12V... but not at 5V...

I'd never design anything that clumsy. And you obviously Spice-fiddled it until you got it to work. At least you got the transition voltage

I can play PSpice in LTspice, but never showed how before...

Copy the following to a file named "Panfilero_LED_4_LTC.cir"

Then OPEN and RUN with LTspice.

Watch for any wrap issues.

• IS=10f CJO=10pF X_D12V N_4 N_5 MyREDLED X_D5V N_3 N_2 MyREDLED V_VPowerSelect VCC 0 DC 0 AC 0

• IS = {IS}
• RS = {RS}
• N = 1
• EG = 1.11
• BV = {BV}
• IBV = {IBV}
• CJO = {CJO}
• VJ = 0.75
• M = 0.33 ) .ENDS MyZENER

• Cjo=4p
• M=.3333 Vj=.5 Fc=.5 Isr=1.565n Nr=2 Bv=100 Ibv=100u Tt=11.54n)

sheets

must

and

sheets

must

it, and

Too much wine already, John? I snipped the bulk of your .ASC listing to keep the posting short, but marked it for anyone entering the discussion late to the game.

Damn! Maybe _you_ are go "Just advisory. I wasn't criticizing. The libraries in LTspice can mislead."

Cranky old fart >:-} ...Jim Thompson

sheets

must

it, and

it for anyone entering the discussion late to the game.

I was replying to your post that included the full .ASC listing, which made the post rather long.

So I trimmed the .ASC listing to shorten the overall message but added a link to the full message if anyone missed it.

Capish ?:-)

Next time I'll leave an explanatory note for any of you who are mentally slowing down >:-}

Note to Larkin and his butt buddies:

See!! Fields and I will cut each other's throat, if necessary to make a point ;-) ...Jim Thompson

The point being that you are both crabby old hens.

Hey, we all knew that already.

--

John Larkin Highland Technology, Inc

jlarkin at highlandtechnology dot com

Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation

before JF

get

yet a pen,

is

you

file

fiddle

You clearly DID NOT READ what i posted. Lame flame.

?-)

JF

pen,

Yup. A lame flame from a lame brain >:-} ...Jim Thompson

sometimes sheets

must

Poor self deluded Larkin, doesn't understand braggadocio is an insult, similar to "talking trash" or lying.

that and

it, and

sometimes sheets

"braggadocio" you must

mostly

inverting it, and

That is true, every spice can. I wish LTspice had a complete set of LT parts as well, but it doesn't.

?-)

sometimes sheets

must

it, and

I'm working my way thru "talking" to LTspice from other simulators. Some peculiarities... LTspice doesn't treat ".LIB" like other simulators, more like it behaves as ".INC", which barfs on components you haven't even called out to use in your schematic :-( ...Jim Thompson

sheets

and

and

Clueless white trash is the BEST descriptor I can find for Larkin. ...Jim Thompson

sheets

Post a circuit yourself. Whine or design.

sometimes sheets

must

it, and

And I've just figured out why. PSpice "indexes" a library, so there's both a .LIB file and a matching .IND file. PSpice uses the .IND file to quickly grab, and put into memory, only those parts in the schematic. LTspice loads the whole library and checks it for LTspice compatibility :-( ...Jim Thompson

Just so long as you don't adopt his "signature" catchprase.

Not much use as a design, then...

Don't you mean "prescribed"?

"Proscribed" means "forbidden".

-- "For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." (Richard Feynman)