simple one-shot pulse detector circuit needed

Guest
Hi all,

I seem to recall from distant memory that it's possible to make a pulse detector out of two of transistors and a few resistors, but I can't find the circuit anywhere. Searches keep throwing up stuff about astable multivibrators and nand gates and that's not what I'm looking for.

Just need to be able to detect a 1 second pulse of 5v on an otherwise 0v line. The pulse comes only after several days of inactivity and should turn an LED on permanently. No reset required and any subsequent pulses must *not* turn the LED off again, so it's operating like a bistable latch (if that's the right term).

Can anyone assist?

Tia.
 
On Nov 20, 8:15 am, orion.osi...@virgin.net wrote:
Hi all,

I seem to recall from distant memory that it's possible to make a pulse detector out of two of transistors and a few resistors, but I can't find the circuit anywhere. Searches keep throwing up stuff about astable multivibrators and nand gates and that's not what I'm looking for.

Just need to be able to detect a 1 second pulse of 5v on an otherwise 0v line. The pulse comes only after several days of inactivity and should turn an LED on permanently. No reset required and any subsequent pulses must *not* turn the LED off again, so it's operating like a bistable latch (if that's the right term).

Can anyone assist?

Tia.
Click to expand...
I assume there is another power line to run it from (+5 V). I don't
know the transistor circuit, but how about a S/R flip flop?

George H.
 
On Tue, 20 Nov 2012 05:15:02 -0800 (PST), orion.osiris@virgin.net
wrote:

Hi all,

I seem to recall from distant memory that it's possible to make a pulse detector out of two of transistors and a few resistors, but I can't find the circuit anywhere. Searches keep throwing up stuff about astable multivibrators and nand gates and that's not what I'm looking for.

Just need to be able to detect a 1 second pulse of 5v on an otherwise 0v line. The pulse comes only after several days of inactivity and should turn an LED on permanently. No reset required and any subsequent pulses must *not* turn the LED off again, so it's operating like a bistable latch (if that's the right term).

Can anyone assist?

Tia.
Click to expand...
---
Version 4
SHEET 1 880 680
WIRE 16 -192 -496 -192
WIRE 160 -192 16 -192
WIRE 16 -144 16 -192
WIRE 160 -144 160 -192
WIRE 16 48 16 -64
WIRE 160 96 160 -64
WIRE 160 96 80 96
WIRE 160 128 160 96
WIRE 160 224 160 192
WIRE -352 272 -400 272
WIRE -208 272 -272 272
WIRE -128 272 -208 272
WIRE 16 272 16 144
WIRE 16 272 -64 272
WIRE 96 272 16 272
WIRE -496 304 -496 -192
WIRE -400 304 -400 272
WIRE -208 320 -208 272
WIRE -496 432 -496 384
WIRE -400 432 -400 384
WIRE -400 432 -496 432
WIRE -208 432 -208 384
WIRE -208 432 -400 432
WIRE 160 432 160 320
WIRE 160 432 -208 432
WIRE -496 496 -496 432
FLAG -496 496 0
SYMBOL res 144 -160 R0
SYMATTR InstName R1
SYMATTR Value 39
SYMATTR SpiceLine ""
SYMBOL npn 96 224 R0
SYMATTR InstName Q1
SYMATTR Value 2N3904
SYMBOL pnp 80 144 R180
SYMATTR InstName Q2
SYMATTR Value 2N3906
SYMBOL diode -128 288 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D1
SYMATTR Value 1N4148
SYMBOL res -256 256 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R2
SYMATTR Value 68k
SYMATTR SpiceLine ""
SYMBOL cap -224 320 R0
SYMATTR InstName C1
SYMATTR Value 47ľ
SYMATTR SpiceLine ""
SYMBOL LED 144 128 R0
SYMATTR InstName D2
SYMATTR Value NSCW100
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL voltage -400 288 R0
WINDOW 3 24 96 Invisible 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value PULSE(0 5 1 1u 1u 1 0 1)
SYMATTR Value2 ""
SYMATTR SpiceLine ""
SYMBOL voltage -496 288 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value 10
SYMATTR Value2 ""
SYMATTR SpiceLine ""
SYMBOL res 0 -160 R0
SYMATTR InstName R4
SYMATTR Value 1000
SYMATTR SpiceLine ""
TEXT -530 520 Left 2 !.tran 3 startup


--
JF
 
On Tue, 20 Nov 2012, orion.osiris@virgin.net wrote:

Hi all,

I seem to recall from distant memory that it's possible to make a pulse
detector out of two of transistors and a few resistors, but I can't find
the circuit anywhere. Searches keep throwing up stuff about astable
multivibrators and nand gates and that's not what I'm looking for.

Just need to be able to detect a 1 second pulse of 5v on an otherwise 0v
line. The pulse comes only after several days of inactivity and should
turn an LED on permanently. No reset required and any subsequent pulses
must *not* turn the LED off again, so it's operating like a bistable
latch (if that's the right term).

Can anyone assist?

Tia.

An SCR would do it, once triggered it only turns off if it loses power on
Click to expand...
the anode.

You can get the effect of an SCR with two transistors, at least for this
purpose. I can't remember, but doing a search for something like that
should do it.

Michael
 
On Tue, 20 Nov 2012 11:22:52 -0600, John Fields
<jfields@austininstruments.com> wrote:

On Tue, 20 Nov 2012 05:15:02 -0800 (PST), orion.osiris@virgin.net
wrote:

Hi all,

I seem to recall from distant memory that it's possible to make a pulse detector out of two of transistors and a few resistors, but I can't find the circuit anywhere. Searches keep throwing up stuff about astable multivibrators and nand gates and that's not what I'm looking for.

Just need to be able to detect a 1 second pulse of 5v on an otherwise 0v line. The pulse comes only after several days of inactivity and should turn an LED on permanently. No reset required and any subsequent pulses must *not* turn the LED off again, so it's operating like a bistable latch (if that's the right term).

Can anyone assist?

Tia.
Click to expand...
Now make it blink miser-style, as in LM3909 ;-)

---
Version 4
SHEET 1 880 680
WIRE 16 -192 -496 -192
Click to expand...
[snip, details in...]

Message-ID: <g1fna89d8usoqgeva1m2g7gkop3e7e4h0k@4ax.com>

SYMATTR SpiceLine ""
TEXT -530 520 Left 2 !.tran 3 startup
Click to expand...
...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
On Nov 20, 12:22 pm, John Fields <jfie...@austininstruments.com>
wrote:
On Tue, 20 Nov 2012 05:15:02 -0800 (PST), orion.osi...@virgin.net
wrote:

Hi all,

I seem to recall from distant memory that it's possible to make a pulse detector out of two of transistors and a few resistors, but I can't find the circuit anywhere. Searches keep throwing up stuff about astable multivibrators and nand gates and that's not what I'm looking for.

Just need to be able to detect a 1 second pulse of 5v on an otherwise 0v line. The pulse comes only after several days of inactivity and should turn an LED on permanently. No reset required and any subsequent pulses must *not* turn the LED off again, so it's operating like a bistable latch (if that's the right term).

Can anyone assist?

Tia.

---
Version 4
SHEET 1 880 680
WIRE 16 -192 -496 -192
WIRE 160 -192 16 -192
WIRE 16 -144 16 -192
WIRE 160 -144 160 -192
WIRE 16 48 16 -64
WIRE 160 96 160 -64
WIRE 160 96 80 96
WIRE 160 128 160 96
WIRE 160 224 160 192
WIRE -352 272 -400 272
WIRE -208 272 -272 272
WIRE -128 272 -208 272
WIRE 16 272 16 144
WIRE 16 272 -64 272
WIRE 96 272 16 272
WIRE -496 304 -496 -192
WIRE -400 304 -400 272
WIRE -208 320 -208 272
WIRE -496 432 -496 384
WIRE -400 432 -400 384
WIRE -400 432 -496 432
WIRE -208 432 -208 384
WIRE -208 432 -400 432
WIRE 160 432 160 320
WIRE 160 432 -208 432
WIRE -496 496 -496 432
FLAG -496 496 0
SYMBOL res 144 -160 R0
SYMATTR InstName R1
SYMATTR Value 39
SYMATTR SpiceLine ""
SYMBOL npn 96 224 R0
SYMATTR InstName Q1
SYMATTR Value 2N3904
SYMBOL pnp 80 144 R180
SYMATTR InstName Q2
SYMATTR Value 2N3906
SYMBOL diode -128 288 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D1
SYMATTR Value 1N4148
SYMBOL res -256 256 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R2
SYMATTR Value 68k
SYMATTR SpiceLine ""
SYMBOL cap -224 320 R0
SYMATTR InstName C1
SYMATTR Value 47
SYMATTR SpiceLine ""
SYMBOL LED 144 128 R0
SYMATTR InstName D2
SYMATTR Value NSCW100
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL voltage -400 288 R0
WINDOW 3 24 96 Invisible 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value PULSE(0 5 1 1u 1u 1 0 1)
SYMATTR Value2 ""
SYMATTR SpiceLine ""
SYMBOL voltage -496 288 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value 10
SYMATTR Value2 ""
SYMATTR SpiceLine ""
SYMBOL res 0 -160 R0
SYMATTR InstName R4
SYMATTR Value 1000
SYMATTR SpiceLine ""
TEXT -530 520 Left 2 !.tran 3 startup

--
JF
Click to expand...
Nice... but I had to reduce C1 from 47 Farads to 47nF :^)

George H.
 
On Nov 20, 6:22 pm, John Fields wrote:
---
Version 4
SHEET 1 880 680
WIRE 16 -192 -496 -192
WIRE 160 -192 16 -192
WIRE 16 -144 16 -192
WIRE 160 -144 160 -192
WIRE 16 48 16 -64
WIRE 160 96 160 -64
WIRE 160 96 80 96
WIRE 160 128 160 96
WIRE 160 224 160 192
WIRE -352 272 -400 272
WIRE -208 272 -272 272
WIRE -128 272 -208 272
WIRE 16 272 16 144
WIRE 16 272 -64 272
WIRE 96 272 16 272
WIRE -496 304 -496 -192
WIRE -400 304 -400 272
WIRE -208 320 -208 272
WIRE -496 432 -496 384
WIRE -400 432 -400 384
WIRE -400 432 -496 432
WIRE -208 432 -208 384
WIRE -208 432 -400 432
WIRE 160 432 160 320
WIRE 160 432 -208 432
WIRE -496 496 -496 432
FLAG -496 496 0
SYMBOL res 144 -160 R0
SYMATTR InstName R1
SYMATTR Value 39
SYMATTR SpiceLine ""
SYMBOL npn 96 224 R0
SYMATTR InstName Q1
SYMATTR Value 2N3904
SYMBOL pnp 80 144 R180
SYMATTR InstName Q2
SYMATTR Value 2N3906
SYMBOL diode -128 288 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D1
SYMATTR Value 1N4148
SYMBOL res -256 256 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R2
SYMATTR Value 68k
SYMATTR SpiceLine ""
SYMBOL cap -224 320 R0
SYMATTR InstName C1
SYMATTR Value 47
SYMATTR SpiceLine ""
SYMBOL LED 144 128 R0
SYMATTR InstName D2
SYMATTR Value NSCW100
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL voltage -400 288 R0
WINDOW 3 24 96 Invisible 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value PULSE(0 5 1 1u 1u 1 0 1)
SYMATTR Value2 ""
SYMATTR SpiceLine ""
SYMBOL voltage -496 288 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value 10
SYMATTR Value2 ""
SYMATTR SpiceLine ""
SYMBOL res 0 -160 R0
SYMATTR InstName R4
SYMATTR Value 1000
SYMATTR SpiceLine ""
TEXT -530 520 Left 2 !.tran 3 startup

--
JF
Click to expand...
Can't get this to run for some reason, John. This is a LT spice
netlist? Just get the following error message: "multiple instances of
SYMATTR" Since someone else on this thread seems to have got it going
(albeit with a slight mod to a cap value) I assume I'm doing something
wrong (not an unknown experience).
 
On Nov 20, 8:15 pm, Michael Black <et...@ncf.ca> wrote:
On Tue, 20 Nov 2012, orion.osi...@virgin.net wrote:
Hi all,

I seem to recall from distant memory that it's possible to make a pulse
detector out of two of transistors and a few resistors, but I can't find
the circuit anywhere. Searches keep throwing up stuff about astable
multivibrators and nand gates and that's not what I'm looking for.

Just need to be able to detect a 1 second pulse of 5v on an otherwise 0v
line. The pulse comes only after several days of inactivity and should
turn an LED on permanently. No reset required and any subsequent pulses
must *not* turn the LED off again, so it's operating like a bistable
latch (if that's the right term).

Can anyone assist?

Tia.

An SCR would do it, once triggered it only turns off if it loses power on
the anode.

You can get the effect of an SCR with two transistors, at least for this
purpose.  I can't remember, but doing a search for something like that
should do it.

   Michael
Click to expand...
Yes, I'm aware a SCR would be ideal, but I only have great fat
thumping big ones lying around which would be a waste for such a small
signal application.

Malvino's book Electronic Principles shows the kind of thing I'm
talking about, I've just discovered, at page 501. Vanishingly terse
explanation with no reference to it in the index or contents for some
reason. Uses a BJT PNP/NPN pair with bases and collectors shorted
together between them and one resistor in the Vcc line. I reckon this
should do the trick with any luck.
 
On Nov 20, 6:55 pm, phaedrus <orion.osi...@virgin.net> wrote:
On Nov 20, 6:22 pm, John Fields wrote:







---
Version 4
SHEET 1 880 680
WIRE 16 -192 -496 -192
WIRE 160 -192 16 -192
WIRE 16 -144 16 -192
WIRE 160 -144 160 -192
WIRE 16 48 16 -64
WIRE 160 96 160 -64
WIRE 160 96 80 96
WIRE 160 128 160 96
WIRE 160 224 160 192
WIRE -352 272 -400 272
WIRE -208 272 -272 272
WIRE -128 272 -208 272
WIRE 16 272 16 144
WIRE 16 272 -64 272
WIRE 96 272 16 272
WIRE -496 304 -496 -192
WIRE -400 304 -400 272
WIRE -208 320 -208 272
WIRE -496 432 -496 384
WIRE -400 432 -400 384
WIRE -400 432 -496 432
WIRE -208 432 -208 384
WIRE -208 432 -400 432
WIRE 160 432 160 320
WIRE 160 432 -208 432
WIRE -496 496 -496 432
FLAG -496 496 0
SYMBOL res 144 -160 R0
SYMATTR InstName R1
SYMATTR Value 39
SYMATTR SpiceLine ""
SYMBOL npn 96 224 R0
SYMATTR InstName Q1
SYMATTR Value 2N3904
SYMBOL pnp 80 144 R180
SYMATTR InstName Q2
SYMATTR Value 2N3906
SYMBOL diode -128 288 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D1
SYMATTR Value 1N4148
SYMBOL res -256 256 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R2
SYMATTR Value 68k
SYMATTR SpiceLine ""
SYMBOL cap -224 320 R0
SYMATTR InstName C1
SYMATTR Value 47
SYMATTR SpiceLine ""
SYMBOL LED 144 128 R0
SYMATTR InstName D2
SYMATTR Value NSCW100
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL voltage -400 288 R0
WINDOW 3 24 96 Invisible 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value PULSE(0 5 1 1u 1u 1 0 1)
SYMATTR Value2 ""
SYMATTR SpiceLine ""
SYMBOL voltage -496 288 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value 10
SYMATTR Value2 ""
SYMATTR SpiceLine ""
SYMBOL res 0 -160 R0
SYMATTR InstName R4
SYMATTR Value 1000
SYMATTR SpiceLine ""
TEXT -530 520 Left 2 !.tran 3 startup

--
JF

Can't get this to run for some reason, John. This is a LT spice
netlist? Just get the following error message: "multiple instances of
SYMATTR" Since someone else on this thread seems to have got it going
(albeit with a slight mod to a cap value) I assume I'm doing something
wrong (not an unknown experience).- Hide quoted text -

- Show quoted text -
Click to expand...
Hmm, I just cut and pasted the whole thing into notepad... or pick
some other text editor.
Then save it with a .asc ending, into my ltspice/bin and run it.

George H.
 
On 2012-11-20, orion.osiris@virgin.net <orion.osiris@virgin.net> wrote:
Hi all,

I seem to recall from distant memory that it's possible to make a pulse detector out of two of transistors and a few resistors, but I can't find the circuit anywhere. Searches keep throwing up stuff about astable multivibrators and nand gates and that's not what I'm looking for.

Just need to be able to detect a 1 second pulse of 5v on an otherwise 0v line. The pulse comes only after several days of inactivity and should turn an LED on permanently. No reset required and any subsequent pulses must *not* turn the LED off again, so it's operating like a bistable latch (if that's the right term).

Can anyone assist?
Click to expand...
just make an SCR out of your two transistors.

one resistor on the gate input and a series resistor to limit the LED
current.


--
⚂⚃ 100% natural

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---
 
On Tue, 20 Nov 2012 12:22:00 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Tue, 20 Nov 2012 11:22:52 -0600, John Fields
jfields@austininstruments.com> wrote:

On Tue, 20 Nov 2012 05:15:02 -0800 (PST), orion.osiris@virgin.net
wrote:

Hi all,

I seem to recall from distant memory that it's possible to make a pulse detector out of two of transistors and a few resistors, but I can't find the circuit anywhere. Searches keep throwing up stuff about astable multivibrators and nand gates and that's not what I'm looking for.

Just need to be able to detect a 1 second pulse of 5v on an otherwise 0v line. The pulse comes only after several days of inactivity and should turn an LED on permanently. No reset required and any subsequent pulses must *not* turn the LED off again, so it's operating like a bistable latch (if that's the right term).

Can anyone assist?

Tia.

Now make it blink miser-style, as in LM3909 ;-)


---
Version 4
SHEET 1 880 680
WIRE 16 -192 -496 -192

[snip, details in...]

Message-ID: <g1fna89d8usoqgeva1m2g7gkop3e7e4h0k@4ax.com

SYMATTR SpiceLine ""
TEXT -530 520 Left 2 !.tran 3 startup

...Jim Thompson
Click to expand...
---
What are you talking about?

--
JF
 
On Wed, 21 Nov 2012 11:20:11 -0600, John Fields
<jfields@austininstruments.com> wrote:

On Tue, 20 Nov 2012 12:22:00 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Tue, 20 Nov 2012 11:22:52 -0600, John Fields
jfields@austininstruments.com> wrote:

On Tue, 20 Nov 2012 05:15:02 -0800 (PST), orion.osiris@virgin.net
wrote:

Hi all,

I seem to recall from distant memory that it's possible to make a pulse detector out of two of transistors and a few resistors, but I can't find the circuit anywhere. Searches keep throwing up stuff about astable multivibrators and nand gates and that's not what I'm looking for.

Just need to be able to detect a 1 second pulse of 5v on an otherwise 0v line. The pulse comes only after several days of inactivity and should turn an LED on permanently. No reset required and any subsequent pulses must *not* turn the LED off again, so it's operating like a bistable latch (if that's the right term).

Can anyone assist?

Tia.

Now make it blink miser-style, as in LM3909 ;-)


---
Version 4
SHEET 1 880 680
WIRE 16 -192 -496 -192

[snip, details in...]

Message-ID: <g1fna89d8usoqgeva1m2g7gkop3e7e4h0k@4ax.com

SYMATTR SpiceLine ""
TEXT -530 520 Left 2 !.tran 3 startup

...Jim Thompson

---
What are you talking about?
Click to expand...
Once tripped, have it blink to save power. (I'm thinking battery
power.)

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
On Wed, 21 Nov 2012 12:28:12 -0800 (PST), phaedrus
<orion.osiris@virgin.net> wrote:

On Nov 21, 6:30 pm, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My-
Web-Site.com> wrote:
On Wed, 21 Nov 2012 11:20:11 -0600, John Fields

---
What are you talking about?

Once tripped, have it blink to save power.  (I'm thinking battery
power.)

                                        ...Jim Thompson

I gathered that, Jim. Good suggestion on your part; I just can't get
that link to bring up any results for some reason. :(
Click to expand...
---
Here's the circuit list again, just in case...


Version 4
SHEET 1 880 680
WIRE 16 -192 -496 -192
WIRE 160 -192 16 -192
WIRE 16 -144 16 -192
WIRE 160 -144 160 -192
WIRE 16 0 16 -64
WIRE 160 48 160 -64
WIRE 160 48 80 48
WIRE 160 80 160 48
WIRE 160 176 160 144
WIRE -352 224 -400 224
WIRE -208 224 -272 224
WIRE -128 224 -208 224
WIRE 16 224 16 96
WIRE 16 224 -64 224
WIRE 96 224 16 224
WIRE -496 256 -496 -192
WIRE -400 256 -400 224
WIRE -208 272 -208 224
WIRE 160 320 160 272
WIRE -496 432 -496 336
WIRE -400 432 -400 336
WIRE -400 432 -496 432
WIRE -208 432 -208 336
WIRE -208 432 -400 432
WIRE 160 432 160 400
WIRE 160 432 -208 432
WIRE -496 496 -496 432
FLAG -496 496 0
SYMBOL res 144 -160 R0
SYMATTR InstName R1
SYMATTR Value 330
SYMATTR SpiceLine ""
SYMBOL npn 96 176 R0
SYMATTR InstName Q1
SYMATTR Value 2N3904
SYMBOL pnp 80 96 R180
SYMATTR InstName Q2
SYMATTR Value 2N3906
SYMBOL diode -128 240 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D1
SYMATTR Value 1N4148
SYMBOL res -256 208 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R2
SYMATTR Value 68k
SYMATTR SpiceLine ""
SYMBOL cap -224 272 R0
SYMATTR InstName C1
SYMATTR Value 47ľ
SYMATTR SpiceLine ""
SYMBOL LED 144 80 R0
SYMATTR InstName D2
SYMATTR Value NSCW100
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL voltage -400 240 R0
WINDOW 3 24 96 Invisible 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR Value PULSE(0 5 1 1u 1u 1 0 1)
SYMATTR Value2 ""
SYMATTR SpiceLine ""
SYMATTR InstName V1
SYMBOL voltage -496 240 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR Value2 ""
SYMATTR SpiceLine ""
SYMATTR InstName V2
SYMATTR Value 10
SYMBOL res 0 -160 R0
SYMATTR InstName R4
SYMATTR Value 1000
SYMATTR SpiceLine ""
SYMBOL res 144 304 R0
SYMATTR InstName R3
SYMATTR Value 39
SYMATTR SpiceLine ""
TEXT -488 456 Left 2 !.tran 3


Now, here's what to do:

1. On your newsreader's screen, copy the entire list, including
"Version 4", to the clipboard by selecting all the text, then
pressing CTRL-C.

2. Launch Word Pad or any other plain ASCII text editor, and paste the
circuit list into it by pressing Ctrl-V.

3. Using "Save As", assign a filename to the list
(say, "1s pulse detect.asc") and save it to any folder you like.
Make _sure_ the file has a .asc filename extension.

4. Now, navigate over to the folder to where you saved
"1s pulse detect.asc", and left click on the file.

If .asc files are associated with LTspice in your box, then LTspice
will find it and you'll see the schematic pop up.

If that doesn't happen, launch LTspice, navigate to the file, and
left-click on it.

The schematic should appear, and then you can play with the circuit
'til your heart's content.

5. Enjoy! :)

--
JF
 
On Nov 21, 6:30 pm, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My-
Web-Site.com> wrote:
On Wed, 21 Nov 2012 11:20:11 -0600, John Fields









jfie...@austininstruments.com> wrote:
On Tue, 20 Nov 2012 12:22:00 -0700, Jim Thompson
To-Email-Use-The-Envelope-I...@On-My-Web-Site.com> wrote:

On Tue, 20 Nov 2012 11:22:52 -0600, John Fields
jfie...@austininstruments.com> wrote:

On Tue, 20 Nov 2012 05:15:02 -0800 (PST), orion.osi...@virgin.net
wrote:

Hi all,

I seem to recall from distant memory that it's possible to make a pulse detector out of two of transistors and a few resistors, but I can't find the circuit anywhere. Searches keep throwing up stuff about astable multivibrators and nand gates and that's not what I'm looking for.

Just need to be able to detect a 1 second pulse of 5v on an otherwise 0v line. The pulse comes only after several days of inactivity and should turn an LED on permanently. No reset required and any subsequent pulses must *not* turn the LED off again, so it's operating like a bistable latch (if that's the right term).

Can anyone assist?

Tia.

Now make it blink miser-style, as in LM3909 ;-)

---
Version 4
SHEET 1 880 680
WIRE 16 -192 -496 -192

[snip, details in...]

Message-ID: <g1fna89d8usoqgeva1m2g7gkop3e7e4...@4ax.com

SYMATTR SpiceLine ""
TEXT -530 520 Left 2 !.tran 3 startup

                                       ...Jim Thompson

---
What are you talking about?

Once tripped, have it blink to save power.  (I'm thinking battery
power.)

                                        ...Jim Thompson
Click to expand...
I gathered that, Jim. Good suggestion on your part; I just can't get
that link to bring up any results for some reason. :(
 
On Nov 21, 1:38 am, George Herold <gher...@teachspin.com> wrote:

Hmm, I just cut and pasted the whole thing into notepad... or pick
some other text editor.
Then save it with a .asc ending, into my ltspice/bin and run it.

George H.
Click to expand...
I must be having a really bad day, George. Ain't got no such folder on
my system!
 
On Wed, 21 Nov 2012 10:30:40 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Wed, 21 Nov 2012 11:20:11 -0600, John Fields
jfields@austininstruments.com> wrote:
---
What are you talking about?

Once tripped, have it blink to save power. (I'm thinking battery
power.)

...Jim Thompson
Click to expand...
---
news:29esa8pmakmtpl7tq0ra5srgpa8htnloag@4ax.com

--
JF
 
On Thu, 22 Nov 2012 07:14:28 -0800 (PST), phaedrus
<orion.osiris@virgin.net> wrote:


Finally! Thank you, John. Don't know what the problem is this end, but
your list combine with my version of LTS generated a corrupted
schematic with several components rotated and out of position!
Anyway, I was able to reconstruct the corrupted diagram and it now
works fine. Thanks again!
Click to expand...
---
My pleasure. :)

You might want to "synchronize" with LTC by going to:

http://www.linear.com/designtools/software/

and downloading the latest version of LTspice IV.


--
JF
 
On Nov 21, 10:28 pm, John Fields <jfie...@austininstruments.com>
wrote:
On Wed, 21 Nov 2012 12:28:12 -0800 (PST), phaedrus

orion.osi...@virgin.net> wrote:
On Nov 21, 6:30 pm, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My-
Web-Site.com> wrote:
On Wed, 21 Nov 2012 11:20:11 -0600, John Fields
---
What are you talking about?

Once tripped, have it blink to save power. (I'm thinking battery
power.)

...Jim Thompson

I gathered that, Jim. Good suggestion on your part; I just can't get
that link to bring up any results for some reason. :(

---
Here's the circuit list again, just in case...

Version 4
SHEET 1 880 680
WIRE 16 -192 -496 -192
WIRE 160 -192 16 -192
WIRE 16 -144 16 -192
WIRE 160 -144 160 -192
WIRE 16 0 16 -64
WIRE 160 48 160 -64
WIRE 160 48 80 48
WIRE 160 80 160 48
WIRE 160 176 160 144
WIRE -352 224 -400 224
WIRE -208 224 -272 224
WIRE -128 224 -208 224
WIRE 16 224 16 96
WIRE 16 224 -64 224
WIRE 96 224 16 224
WIRE -496 256 -496 -192
WIRE -400 256 -400 224
WIRE -208 272 -208 224
WIRE 160 320 160 272
WIRE -496 432 -496 336
WIRE -400 432 -400 336
WIRE -400 432 -496 432
WIRE -208 432 -208 336
WIRE -208 432 -400 432
WIRE 160 432 160 400
WIRE 160 432 -208 432
WIRE -496 496 -496 432
FLAG -496 496 0
SYMBOL res 144 -160 R0
SYMATTR InstName R1
SYMATTR Value 330
SYMATTR SpiceLine ""
SYMBOL npn 96 176 R0
SYMATTR InstName Q1
SYMATTR Value 2N3904
SYMBOL pnp 80 96 R180
SYMATTR InstName Q2
SYMATTR Value 2N3906
SYMBOL diode -128 240 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D1
SYMATTR Value 1N4148
SYMBOL res -256 208 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R2
SYMATTR Value 68k
SYMATTR SpiceLine ""
SYMBOL cap -224 272 R0
SYMATTR InstName C1
SYMATTR Value 47
SYMATTR SpiceLine ""
SYMBOL LED 144 80 R0
SYMATTR InstName D2
SYMATTR Value NSCW100
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL voltage -400 240 R0
WINDOW 3 24 96 Invisible 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR Value PULSE(0 5 1 1u 1u 1 0 1)
SYMATTR Value2 ""
SYMATTR SpiceLine ""
SYMATTR InstName V1
SYMBOL voltage -496 240 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR Value2 ""
SYMATTR SpiceLine ""
SYMATTR InstName V2
SYMATTR Value 10
SYMBOL res 0 -160 R0
SYMATTR InstName R4
SYMATTR Value 1000
SYMATTR SpiceLine ""
SYMBOL res 144 304 R0
SYMATTR InstName R3
SYMATTR Value 39
SYMATTR SpiceLine ""
TEXT -488 456 Left 2 !.tran 3

Now, here's what to do:

1. On your newsreader's screen, copy the entire list, including
   "Version 4", to the clipboard by selecting all the text, then
   pressing CTRL-C.

2. Launch Word Pad or any other plain ASCII text editor, and paste the
   circuit list into it by  pressing Ctrl-V.

3. Using "Save As", assign a filename to the list
   (say, "1s pulse detect.asc") and save it to any folder you like.
   Make _sure_ the file has a .asc filename extension.

4. Now, navigate over to the folder to where you saved
   "1s pulse detect.asc", and left click on the file.

   If .asc files are associated with LTspice in your box, then LTspice
   will find it and you'll see the schematic pop up.

   If that doesn't happen, launch LTspice, navigate to the file, and
   left-click on it.

   The schematic should appear, and then you can play with the circuit
   'til your heart's content.

5. Enjoy! :)

--
JF
Click to expand...
Finally! Thank you, John. Don't know what the problem is this end, but
your list combine with my version of LTS generated a corrupted
schematic with several components rotated and out of position!
Anyway, I was able to reconstruct the corrupted diagram and it now
works fine. Thanks again!
 
On Thu, 22 Nov 2012 10:10:49 -0600, John Fields
<jfields@austininstruments.com> wrote:

On Thu, 22 Nov 2012 07:14:28 -0800 (PST), phaedrus
orion.osiris@virgin.net> wrote:


Finally! Thank you, John. Don't know what the problem is this end, but
your list combine with my version of LTS generated a corrupted
schematic with several components rotated and out of position!
Anyway, I was able to reconstruct the corrupted diagram and it now
works fine. Thanks again!

---
My pleasure. :)

You might want to "synchronize" with LTC by going to:

http://www.linear.com/designtools/software/

and downloading the latest version of LTspice IV.
Click to expand...
---
Actually, I think the right way to do it is to click on "Tools", "Sync
Release", "OK", and then it'll do it all automagically.


--
JF
 
On Nov 22, 5:20 pm, John Fields <jfie...@austininstruments.com> wrote:
On Thu, 22 Nov 2012 10:10:49 -0600, John Fields









jfie...@austininstruments.com> wrote:
On Thu, 22 Nov 2012 07:14:28 -0800 (PST), phaedrus
orion.osi...@virgin.net> wrote:

Finally! Thank you, John. Don't know what the problem is this end, but
your list combine with my version of LTS generated a corrupted
schematic with several components rotated and out of position!
Anyway, I was able to reconstruct the corrupted diagram and it now
works fine. Thanks again!

---
My pleasure. :)

You might want to "synchronize" with LTC by going to:

http://www.linear.com/designtools/software/

and downloading the latest version of LTspice IV.

---
Actually, I think the right way to do it is to click on "Tools", "Sync
Release", "OK", and then it'll do it all automagically.

--
JF
Click to expand...
Many thanks.
 
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