Chip with simple program for Toy

bw wrote:
"James Arthur" <bogusabdsqy@verizon.net> wrote in message
news:CjCpl.1746$Ez6.582@nwrddc02.gnilink.net...
I posted a couple circuits. Here's the fewest parts I
can manage:


+12v
-+-
|
.-----------------------+
| |
[R1] |
| D1 | |> /
+---|>|------. [relay] | /
| | | O O
| | |
+-----[R2]---+-----. |--'
| | | |<-. Q1
O C1 --- | |--+
\ --- |
\ | ===
O === GND
| GND
===
GND

If R2 = 1000 x R1, and the hold-ON is 3 minutes,
the turn-on time is <180mS.

James Arthur

There are many variations of this delay circuit. For someone testing this
R1=10k
R2=100k
C=100 uF
Should give around 10 second delay. Increase R2 for longer times.
Also, I'd add a 10 volt zener to the Gate of the MOSFET. This makes the
timing easier to modify and allows adapting the circuit for higher supply
voltages by protecting the gate.
I prefer the version with hysteresis for being easier
on the output transistor, but I screwed up--the output's
inverted, I used 'R3' twice, and I left out the diode
across R2.

I'll try to redeem myself.


+12v
-+-
|
.-------------------+----------+
| | |
[R1] [R3] |
| | |<'
| +--[R4]--| Q2
| D2 | |\ PNP
+--|>|---. | .-----+
| | Q1 | | | |> |
+--[R2]--+-----. |--' [D1] [relay] | |
| | | |<-. | | O O
O C1 --- | |--+----+-----'
\ --- |
\ | [R5]
O | |
| === ===
=== GND GND
GND


You don't need a gate protection zener for V+ <20v,
but that's a good idea for when it is.

Cheers,
James Arthur
 
On Thu, 26 Feb 2009 12:50:56 -0800, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Thu, 26 Feb 2009 19:28:44 GMT, Rich Grise <rich@example.net> wrote:

On Thu, 26 Feb 2009 17:13:40 +0000, James Arthur wrote:
...
Maybe I misunderstood,

Nope.

but wasn't the goal to engage a
relay when a switch opens, then release the relay a minute
or two or three after the switch re-closes?

Yup:
"The goal is to turn on a 12v relay with a switch that is closed when off
and open when on."

O frabjous day! Callooh! Callay! Both Johns have scresed one up today!
;-D


The original description wasn't a model of clarity.
---
Onward through the fog. Seems a couple of us got it, you not included,
first time out.
---

But if you keep score and rejoice in mistakes, enjoy.
---
Oh, my... how passive aggressive.

A guilt trip you'd like to have laid on us for finding "the Larkin" at
fault?

It's not about rejoicing in mistakes, its about rejoicing in catching
those who profess to be free from making mistakes and, when they do,
blaming it on someone else.

Your: "The original description wasn't a model of clarity." is a prime
example, since you blamed the OP for _your_ inability to understand what
he was talking about, while at least two of us did.

JF
 
On Thu, 26 Feb 2009 19:11:49 -0600, John Fields
<jfields@austininstruments.com> wrote:

On Thu, 26 Feb 2009 12:50:56 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

[snip]

The original description wasn't a model of clarity.

---
Onward through the fog. Seems a couple of us got it, you not included,
first time out.
---

But if you keep score and rejoice in mistakes, enjoy.

---
Oh, my... how passive aggressive.
Bwahahahahaha! Damn! Almost snorted wine up my nose :-(

A guilt trip you'd like to have laid on us for finding "the Larkin" at
fault?

It's not about rejoicing in mistakes, its about rejoicing in catching
those who profess to be free from making mistakes and, when they do,
blaming it on someone else.

Your: "The original description wasn't a model of clarity." is a prime
example, since you blamed the OP for _your_ inability to understand what
he was talking about, while at least two of us did.

JF
Bwahahahahahaha!

...Jim Thompson
--
| James E.Thompson, P.E. | 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 |

If we knew what we were doing, it wouldn't be called research...
-- Albert Einstein
 
Jim Thompson wrote:
On Thu, 26 Feb 2009 19:11:49 -0600, John Fields
jfields@austininstruments.com> wrote:

On Thu, 26 Feb 2009 12:50:56 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

[snip]
The original description wasn't a model of clarity.
---
Onward through the fog. Seems a couple of us got it, you not included,
first time out.
---

But if you keep score and rejoice in mistakes, enjoy.
---
Oh, my... how passive aggressive.

Bwahahahahaha! Damn! Almost snorted wine up my nose :-(

A guilt trip you'd like to have laid on us for finding "the Larkin" at
fault?

It's not about rejoicing in mistakes, its about rejoicing in catching
those who profess to be free from making mistakes and, when they do,
blaming it on someone else.

Your: "The original description wasn't a model of clarity." is a prime
example, since you blamed the OP for _your_ inability to understand what
he was talking about, while at least two of us did.

JF

Bwahahahahahaha!

...Jim Thompson

Now now boys, we've got better things to jaw about. Check out the
Newshour on PBS re: the budget. Stunning.

The Nightly Business Report too. Yikes.

Cheers,
James Arthur
 
On Fri, 27 Feb 2009 01:39:24 GMT, James Arthur
<bogusabdsqy@verizon.net> wrote:

Jim Thompson wrote:
On Thu, 26 Feb 2009 19:11:49 -0600, John Fields
jfields@austininstruments.com> wrote:

On Thu, 26 Feb 2009 12:50:56 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

[snip]
The original description wasn't a model of clarity.
---
Onward through the fog. Seems a couple of us got it, you not included,
first time out.
---

But if you keep score and rejoice in mistakes, enjoy.
---
Oh, my... how passive aggressive.

Bwahahahahaha! Damn! Almost snorted wine up my nose :-(

A guilt trip you'd like to have laid on us for finding "the Larkin" at
fault?

It's not about rejoicing in mistakes, its about rejoicing in catching
those who profess to be free from making mistakes and, when they do,
blaming it on someone else.

Your: "The original description wasn't a model of clarity." is a prime
example, since you blamed the OP for _your_ inability to understand what
he was talking about, while at least two of us did.

JF

Bwahahahahahaha!

...Jim Thompson


Now now boys, we've got better things to jaw about. Check out the
Newshour on PBS re: the budget. Stunning.

The Nightly Business Report too. Yikes.

Cheers,
James Arthur
I don't want to watch something like that... it would upset me so much
I couldn't enjoy the nice (French-style) pot roast about to be served.

And I'm sipping a nice Coppola Diamond Collection 2006 Black Label
Claret ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | 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 |

With all this hope and change, all you need is a dab of mayonaisse
and you'll have a tasty lunch on which you will choke to death.
 
Jim Thompson wrote:
On Fri, 27 Feb 2009 01:39:24 GMT, James Arthur
bogusabdsqy@verizon.net> wrote:


Now now boys, we've got better things to jaw about. Check out the
Newshour on PBS re: the budget. Stunning.

The Nightly Business Report too. Yikes.

Cheers,
James Arthur

I don't want to watch something like that... it would upset me so much
I couldn't enjoy the nice (French-style) pot roast about to be served.

And I'm sipping a nice Coppola Diamond Collection 2006 Black Label
Claret ;-)

...Jim Thompson
Enjoy!

James Arthur
 
On Thu, 26 Feb 2009 19:11:49 -0600, John Fields
<jfields@austininstruments.com> wrote:

On Thu, 26 Feb 2009 12:50:56 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Thu, 26 Feb 2009 19:28:44 GMT, Rich Grise <rich@example.net> wrote:

On Thu, 26 Feb 2009 17:13:40 +0000, James Arthur wrote:
...
Maybe I misunderstood,

Nope.

but wasn't the goal to engage a
relay when a switch opens, then release the relay a minute
or two or three after the switch re-closes?

Yup:
"The goal is to turn on a 12v relay with a switch that is closed when off
and open when on."

O frabjous day! Callooh! Callay! Both Johns have scresed one up today!
;-D


The original description wasn't a model of clarity.

---
Onward through the fog. Seems a couple of us got it, you not included,
first time out.
---

But if you keep score and rejoice in mistakes, enjoy.

---
Oh, my... how passive aggressive.

A guilt trip you'd like to have laid on us for finding "the Larkin" at
fault?

It's not about rejoicing in mistakes, its about rejoicing in catching
those who profess to be free from making mistakes and, when they do,
blaming it on someone else.
I make mistakes all the time, some here. And I freely admit the ones
that are obvious. We just sometimes disagree on what's actually a
mistake.

Your: "The original description wasn't a model of clarity." is a prime
example, since you blamed the OP for _your_ inability to understand what
he was talking about, while at least two of us did.

JF
Get a life. You're turning into an old hen, strutting and clucking.

If I misunderstood the OP's polarities, so what?

Get a life.

John
 
On Thu, 26 Feb 2009 18:23:57 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote:

On Thu, 26 Feb 2009 19:11:49 -0600, John Fields
jfields@austininstruments.com> wrote:

On Thu, 26 Feb 2009 12:50:56 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

[snip]

The original description wasn't a model of clarity.

---
Onward through the fog. Seems a couple of us got it, you not included,
first time out.
---

But if you keep score and rejoice in mistakes, enjoy.

---
Oh, my... how passive aggressive.

Bwahahahahaha! Damn! Almost snorted wine up my nose :-(


A guilt trip you'd like to have laid on us for finding "the Larkin" at
fault?

It's not about rejoicing in mistakes, its about rejoicing in catching
those who profess to be free from making mistakes and, when they do,
blaming it on someone else.

Your: "The original description wasn't a model of clarity." is a prime
example, since you blamed the OP for _your_ inability to understand what
he was talking about, while at least two of us did.

JF

Bwahahahahahaha!

...Jim Thompson
TWO old hens.

John
 
On Thu, 26 Feb 2009 17:25:21 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote:

On Thu, 26 Feb 2009 16:22:01 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Thu, 26 Feb 2009 17:11:26 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote:

On Thu, 26 Feb 2009 15:51:15 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Thu, 26 Feb 2009 13:35:10 -0600, John Fields
jfields@austininstruments.com> wrote:

On Thu, 26 Feb 2009 08:45:47 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Thu, 26 Feb 2009 10:32:55 -0600, John Fields
jfields@austininstruments.com> wrote:

On Thu, 26 Feb 2009 09:14:12 -0600, John Fields
jfields@austininstruments.com> wrote:


---
But... something esle was running around in my head and here it is:
a _much, much_ better way to do it, Duh...



Or just...


+V>-----------+--------+-----+----+--------+
| |
[1M] [COIL]
| |
| e
____ | / -----b pnp darlington or
O O---+------------------/ c low threshold pfet
| | |
| [68ľF] |
| | |
GND>---+------+--------+-----+-------------+

---
Huh???

RTFM

JF

Keep working on your 555 thing. If you add enough parts, you may
eventually get it right.

John

John L, Methinks you need to revisit the original SOW, before
throwing stones...

"I'm ok with fixing and adapting circuits but not so good with design.
I've come up with an electronic switch circuit but I think it could
use improvement. The goal is to turn on a 12v relay with a switch
that is closed when off and open when on. The switch also has to have
one leg grounded. It's a pressure switch with a single terminal. I
also want the relay to stay closed (on) for a couple minutes when the
switch goes from on (open) to off (closed). Here's what I've got now
and it does work. But I had to use a pretty big capacitor and I'm
still only getting about a minute of delay when going to the off
state. Because I can't make the 10k resistor any bigger. I'm
thinking that it is likely possible to get a longer delay and do it
with a smaller capacitor if I was better at designing this. The other
flaw is that this slowly lowers the voltage to the relay until it
drops. The relay stays pulled to about 3 to 4 volts. I also suspect
there is a better way to keep it fully on until the rc timer expires.
Thanks in advance for any suggestions :)"


...Jim Thompson


I'm sure you and Rich will post some great circuits and show us how
wrong we are.

John


You threw stones at John F, then posted a very soft transition
solution... did you not?
I called him an old hen, which is pretty accurate. What's wrong with
soft turnoff of a relay? The armature stays seated until it doesn't.

Did you bang your head badly during that skiing spill ?:)
Nope, skiers and motorcyclists don't often land on their heads. That's
for snowboarders and horse riders.

Hey, post a relay delay circuit of your own and quit clucking. You're
turning into the village gossip.

John
 
On Thu, 26 Feb 2009 18:11:58 -0800, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Thu, 26 Feb 2009 18:23:57 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote:

On Thu, 26 Feb 2009 19:11:49 -0600, John Fields
jfields@austininstruments.com> wrote:

On Thu, 26 Feb 2009 12:50:56 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

[snip]

The original description wasn't a model of clarity.

---
Onward through the fog. Seems a couple of us got it, you not included,
first time out.
---

But if you keep score and rejoice in mistakes, enjoy.

---
Oh, my... how passive aggressive.

Bwahahahahaha! Damn! Almost snorted wine up my nose :-(


A guilt trip you'd like to have laid on us for finding "the Larkin" at
fault?

It's not about rejoicing in mistakes, its about rejoicing in catching
those who profess to be free from making mistakes and, when they do,
blaming it on someone else.

Your: "The original description wasn't a model of clarity." is a prime
example, since you blamed the OP for _your_ inability to understand what
he was talking about, while at least two of us did.

JF

Bwahahahahahaha!

...Jim Thompson

TWO old hens.

John
Poor baby ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | 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 |

If we knew what we were doing, it wouldn't be called research...
-- Albert Einstein
 
John Larkin wrote:
Did you bang your head badly during that skiing spill ?:)
Nope, skiers and motorcyclists don't often land on their heads. That's
for snowboarders and horse riders.
It can be done though, I know. I don't crash often, but coming off the
side of a slope into rough snow at very high speed once, I jumped off
a little mound and landed on another mound almost 10 metres away...
except it was a minimal bit of snow covering a bush, into which my
skis vanished and stopped. I flew forward out of my bindings and did a
head-plant deep into the soft wet snow a further 8 metres away, and
distinctly recall my neck being in a strange and unusual position as
my whole body flipped violently over the top, wondering if this was
going to be my last thought. Landed flat on my back and got up just
dazed and with a stiff neck, and had to climb back up to get all my
stuff.
 
On Thu, 26 Feb 2009 18:20:34 -0800, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

Nope, skiers and motorcyclists don't often land on their heads. That's
for snowboarders and horse riders.

Tell that to Sonny Bono. Oh... that's right... you can't.

Tell that to Gary Busey. Oh... That's right, he ALSO hit his head from
a bike spill.

No, they may not 'land' on their heads, but they sure do have a high
instance of head trauma involvement in such circumstances. So at some
point while they are wiping out, head impact occurs.
 
On Thu, 26 Feb 2009 19:17:56 -0800, Archimedes' Lever
<OneBigLever@InfiniteSeries.Org> wrote:

On Thu, 26 Feb 2009 18:20:34 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

Nope, skiers and motorcyclists don't often land on their heads. That's
for snowboarders and horse riders.


Tell that to Sonny Bono. Oh... that's right... you can't.
He skied into a tree. By the time he landed, it was pretty much over.

Tell that to Gary Busey. Oh... That's right, he ALSO hit his head from
a bike spill.
It can be done, especially if you ride without a helmet like GB. But
most ski and motorcycle dumps are pretty much horizontal. If you are
going really fast, you can tumble and then it can get nasty.

No, they may not 'land' on their heads, but they sure do have a high
instance of head trauma involvement in such circumstances. So at some
point while they are wiping out, head impact occurs.
Sure. But falling off a horse is a lot more dangerous... good chance
of vertical impact. And snowboarders, going fast downhill across the
slope, can catch an edge and get flung down a slope head-first.

This time on the mountains, I saw a LOT of people, especially
snowboarders, wearing helmets.

John
 
On Thu, 26 Feb 2009 12:28:47 -0500, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

John Larkin wrote:


Looks like hell on my Panasonic dot-matrix printer.


What model? I still have about a dozen on hand.
KXP1624, 24 pin, 14" fanfold. Works great. I go through a box of paper
and a ribbon per project, roughly.

We also have an HP 14" fanfold inkjet, but I like the Panasonic
better. I've heard that there are serious 14" fanfold laser printers,
for serious money. Maybe if I get rich some day...

John
 
On Thu, 26 Feb 2009 15:46:00 -0600, krw <krw@att.zzzzzzzzz> wrote:

In article <UTDpl.1892$tw4.1160@nwrddc01.gnilink.net>,
bogusabdsqy@verizon.net says...
Rich Grise wrote:
On Thu, 26 Feb 2009 06:33:21 +0000, James Arthur wrote:
...
.SBTTL IRQ6 SERVICE

; The HITLOCK mechanism enforces a minimum irq-to-irq delay so
^^^^^^^^^^

IRQ-to-IRQ. There is no "irq". ;-)

Cheers!
Rich


Translating the original I paused at that line and pondered
nearly a full second, flipping it back and forth. It could
go either way.

IRQ_EN, IRQ1, or IRQ_HANDLER would certainly get capitals,
being actual hardware or software elements.

I wouldn't. To aid readability they'd be IRQ_En, IRQ1,
IRQ_Handler, or even InterruptHandler on my schematics, VHDL, and
embedded code.
Sorry, they violate the 6-character symbol limit.

John
 
On Thu, 26 Feb 2009 20:24:11 -0800, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Thu, 26 Feb 2009 15:46:00 -0600, krw <krw@att.zzzzzzzzz> wrote:

In article <UTDpl.1892$tw4.1160@nwrddc01.gnilink.net>,
bogusabdsqy@verizon.net says...
Rich Grise wrote:
On Thu, 26 Feb 2009 06:33:21 +0000, James Arthur wrote:
...
.SBTTL IRQ6 SERVICE

; The HITLOCK mechanism enforces a minimum irq-to-irq delay so
^^^^^^^^^^

IRQ-to-IRQ. There is no "irq". ;-)

Cheers!
Rich


Translating the original I paused at that line and pondered
nearly a full second, flipping it back and forth. It could
go either way.

IRQ_EN, IRQ1, or IRQ_HANDLER would certainly get capitals,
being actual hardware or software elements.

I wouldn't. To aid readability they'd be IRQ_En, IRQ1,
IRQ_Handler, or even InterruptHandler on my schematics, VHDL, and
embedded code.

Sorry, they violate the 6-character symbol limit.
Six characters? Only crappy tools had such draconian restrictions
thirty years ago.
 
On Thu, 26 Feb 2009 19:41:03 GMT, Rich Grise <rich@example.net> wrote:

On Wed, 25 Feb 2009 14:38:34 -0800, John Larkin wrote:

REAL PROGRAMMERS DON'T USE LOWER CASE.

So, how are those FORTRAN FPGAs working out for you? ;-)

Cheers!
Rich
Lots of scientific types still program in FORTRAN. Astronomers, I've
been told.

FORTRAN is now over 50 years old.

John
 
On Thu, 26 Feb 2009 22:30:46 -0600, krw <krw@att.bizzzzzzzzzzz> wrote:

On Thu, 26 Feb 2009 20:24:11 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Thu, 26 Feb 2009 15:46:00 -0600, krw <krw@att.zzzzzzzzz> wrote:

In article <UTDpl.1892$tw4.1160@nwrddc01.gnilink.net>,
bogusabdsqy@verizon.net says...
Rich Grise wrote:
On Thu, 26 Feb 2009 06:33:21 +0000, James Arthur wrote:
...
.SBTTL IRQ6 SERVICE

; The HITLOCK mechanism enforces a minimum irq-to-irq delay so
^^^^^^^^^^

IRQ-to-IRQ. There is no "irq". ;-)

Cheers!
Rich


Translating the original I paused at that line and pondered
nearly a full second, flipping it back and forth. It could
go either way.

IRQ_EN, IRQ1, or IRQ_HANDLER would certainly get capitals,
being actual hardware or software elements.

I wouldn't. To aid readability they'd be IRQ_En, IRQ1,
IRQ_Handler, or even InterruptHandler on my schematics, VHDL, and
embedded code.

Sorry, they violate the 6-character symbol limit.

Six characters? Only crappy tools had such draconian restrictions
thirty years ago.
Do I have to give all the money back?

John
 
On Thu, 26 Feb 2009 18:50:35 GMT, Rich Grise <rich@example.net> wrote:

On Thu, 26 Feb 2009 02:30:47 +0000, Jon Kirwan wrote:

On Wed, 25 Feb 2009 21:52:09 GMT, Rich Grise <rich@example.net> wrote:

snip
Bank-switching is evil.

Only if you think being exposed to hardware that balances competing
needs well is evil.

Were they too cheap (or incompetent) to just stack one on top of the
other (even with mapping for the common ones) and select it with an
address bit?
Have you ever sat down and actually done a micro cpu design? I have.
It's fun. And with cheap FPGA's, it's not even expensive nor does it
require any soldering skills.

Consider the question along the lines of 8-bit widths. You might
understand. If not, I can provide some examples. But it's better
(easier on me) if you think about it a little bit, first.

Jon
 
James Arthur wrote:
bw wrote:
"James Arthur" <bogusabdsqy@verizon.net> wrote in message
news:CjCpl.1746$Ez6.582@nwrddc02.gnilink.net...
I posted a couple circuits. Here's the fewest parts I
can manage:


+12v
-+-
|
.-----------------------+
| |
[R1] |
| D1 | |> /
+---|>|------. [relay] | /
| | | O O
| | |
+-----[R2]---+-----. |--'
| | | |<-. Q1
O C1 --- | |--+
\ --- |
\ | ===
O === GND
| GND
===
GND

If R2 = 1000 x R1, and the hold-ON is 3 minutes,
the turn-on time is <180mS.

James Arthur

There are many variations of this delay circuit. For someone testing this
R1=10k
R2=100k
C=100 uF
Should give around 10 second delay. Increase R2 for longer times.
Also, I'd add a 10 volt zener to the Gate of the MOSFET. This makes
the timing easier to modify and allows adapting the circuit for higher
supply voltages by protecting the gate.

I prefer the version with hysteresis for being easier
on the output transistor, but I screwed up--the output's
inverted, I used 'R3' twice, and I left out the diode
across R2.

I'll try to redeem myself.


+12v
-+-
|
.-------------------+----------+
| | |
[R1] [R3] |
| | |<'
| +--[R4]--| Q2
| D2 | |\ PNP
+--|>|---. | .-----+
| | Q1 | | | |> |
+--[R2]--+-----. |--' [D1] [relay] | |
| | | |<-. | | O O
O C1 --- | |--+----+-----'
\ --- |
\ | [R5]
O | |
| === ===
=== GND GND
GND


You don't need a gate protection zener for V+ <20v,
but that's a good idea for when it is.

Cheers,
James Arthur
Y'know, ASCII-art editing is really a crappy way to
design circuits. You wind up doing the 'art' part
pushing round ASCII at a time when your is brain off
the circuit.

I left an inappropriate feedback path when cut-n-pasting
the above ckt from its predecessor.


+12v
-+-
|
.-------------------+----------+
| | |
[R1] [R3] |
| | |<'
| +--[R4]--| Q2
| D2 | |\ PNP
+--|>|---. | |
| | Q1 | .-----+
+--[R2]--+-----. |--' | | |> |
| | | |<-. [D1] [relay] | |
O C1 --- | |--+ | | O O
\ --- | '-----+
\ | | |
O | | |
| === === ===
=== GND GND GND
GND

There, that's better.
 

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