Maker Pro
Maker Pro

Current reversal in push/pull?

F

Fred Bloggs

Jan 1, 1970
0
Tony said:
We've been here before Fred, a year or so ago.
A transient capacitive voltage doubler, generating
2xVs to pull the solenoid in, dropping back to 1xVs
for holding.

Right- I remember your circuit- but couldn't find it right off in my
files. It went something like this:
View in a fixed-width font such as Courier.


.. V+
.. |
.. +---+----|>|----+------+-------+----+
.. | | | | | |
.. [Rp] | | + | | |
.. | e === - S -
.. | |/ | ^ S ^
.. +--[Rb]-+-| | | S |
.. | |\ | | | |
.. ON c c-----------+------+ +----+
.. -- |/ | |
.. | | -| [Rc] c
.. | | |\ | |/
.. - - e-----------------------|-----[Rb]-+-|
.. | | |\
.. | [Rp] e
.. | | |
.. +----------+---+
.. |
.. .---
.. GND
..
..
..
 
F

Fred Bloggs

Jan 1, 1970
0
Winfield said:
Tony Williams wrote...



Nice. I handed my technician a design for a box with ten
small microwave relays -- except the crazy relays want tight
connections I suppose, and each one takes 5W of coil power!
That's 50W for the set, and it's got me worried about heat.
I can't add a fan, because it's going on a quiet optics bench.
My tech's waiting for parts, so I've got a few days to improve
the coil-power scene.

Tony, did you come up with a slick circuit?

Must be high power...
 
F

Fred Bloggs

Jan 1, 1970
0
Tony said:
We've been here before Fred, a year or so ago.
A transient capacitive voltage doubler, generating
2xVs to pull the solenoid in, dropping back to 1xVs
for holding.

Or maybe it was this:
View in a fixed-width font such as Courier.


..
..
.. V+
.. |
.. +---+----|>|----+------+-------+----+
.. | | | | | |
.. [Rp] | | + | | |
.. | e === - S -
.. | |/ | ^ S ^
.. +-| | | S |
.. | |\ | | | |
.. | c-----------+------+ +----+
.. [Rb] | |
.. | | |
.. | | |
.. +---------------|--------------+
.. | |
.. | |
.. ON [Rc] c
.. -- | |/
.. | | >--|-----[Rb]-+-|
.. | | | | |\
.. - - | [Rp] e
.. | | |
.. +----------+---+
.. |
.. .---
.. GND
..
..
 
F

Fred Bloggs

Jan 1, 1970
0
Tony said:
We've been here before Fred, a year or so ago.
A transient capacitive voltage doubler, generating
2xVs to pull the solenoid in, dropping back to 1xVs
for holding.

Or maybe this for fast recovery- IIRC you posted several mods:
View in a fixed-width font such as Courier.


..
..
.. V+
.. |
.. +---+---+------|>|-+---+----------------+----+
.. | | | | | | |
.. [Rp] | | | + | | |
.. | e | === - S -
.. | |/ | | ^ S ^
.. +-| | | | S |
.. | |\ | | | | |
.. | c--------------+---+ +----+
.. [Rb] | | |
.. | | [Rc] |
.. | | | |
.. +------------------|--------------------+
.. | | | |
.. - | | |
.. ^ [Rbc] c ON c
.. | | |/ -- |/
.. +-------+-|>|--+-| | | >-[Rb]-+-|
.. | |\ | | | |\
.. [Rp] e - - [Rp] e
.. | | | |
.. +---+----------------+---+
.. |
.. .---
.. GND
..
..
 
F

Fred Bloggs

Jan 1, 1970
0
Winfield said:
Tony Williams wrote...



Nice. I handed my technician a design for a box with ten
small microwave relays -- except the crazy relays want tight
connections I suppose, and each one takes 5W of coil power!
That's 50W for the set, and it's got me worried about heat.
I can't add a fan, because it's going on a quiet optics bench.
My tech's waiting for parts, so I've got a few days to improve
the coil-power scene.

Should have bought latching relays- too late now-)
 
F

Fred Bloggs

Jan 1, 1970
0
Tony said:
We've been here before Fred, a year or so ago.
A transient capacitive voltage doubler, generating
2xVs to pull the solenoid in, dropping back to 1xVs
for holding.

There may have been some issue about even a single reverse diode drop
across the storage capacitor- so this will guarantee 0V reverse voltage-
but I still like the feel good diode there anyway- you lose a diode drop
in the drive:
View in a fixed-width font such as Courier.


..
..
.. V+
.. |
.. +---+---+----|>|---+---+----------------+----+
.. | | | | | | |
.. [Rp] | | | + | | |
.. | e | === - S -
.. | |/ | | ^ S ^
.. +-| | | | S |
.. | |\ | | | | |
.. | c--------|>|---+---+ +----+
.. [Rb] | | |
.. | | [Rc] |
.. | | | |
.. +------------------|--------------------+
.. | | | |
.. - | | |
.. ^ [Rbc] c ON c
.. | | |/ -- |/
.. +-------+-|>|--+-| | | >-[Rb]-+-|
.. | |\ | | | |\
.. [Rp] e - - [Rp] e
.. | | | |
.. +---+----------------+---+
.. |
.. .---
.. GND
..
..
 
F

Fred Bloggs

Jan 1, 1970
0
Tony said:
We've been here before Fred, a year or so ago.
A transient capacitive voltage doubler, generating
2xVs to pull the solenoid in, dropping back to 1xVs
for holding.

Maybe use a Schottky diode and linearizing resistor to bleed the few
nanoamps around the capacitor.
View in a fixed-width font such as Courier.


..
..
.. V+
.. | SD
.. +---+---+----|>|---+---+----+-----------+----+
.. | | | | | | | |
.. [Rp] | | | + | | | |
.. | e | === - [10K] S -
.. | |/ | | ^ | S ^
.. +-| | | | | S |
.. | |\ | PND | | | | |
.. | c--------|>|---+---+----+ -+----+
.. [Rb] | | |
.. | | [Rc] |
.. | | | |
.. +------------------|--------------------+
.. | | | |
.. - | | |
.. ^ [Rbc] c ON c
.. | | |/ -- |/
.. +-------+-|>|--+-| | | >-[Rb]-+-|
.. | |\ | | | |\
.. [Rp] e - - [Rp] e
.. | | | |
.. +---+----------------+---+
.. |
.. .---
.. GND
..
..
 
F

Fred Bloggs

Jan 1, 1970
0
Fred said:
Tony said:
We've been here before Fred, a year or so ago.
A transient capacitive voltage doubler, generating
2xVs to pull the solenoid in, dropping back to 1xVs
for holding.

Maybe use a Schottky diode and linearizing resistor to bleed the few
nanoamps around the capacitor.
View in a fixed-width font such as Courier.


.
.
. V+
. | SD
. +---+---+----|>|---+---+----+-----------+----+
. | | | | | | | |
. [Rp] | | | + | | | |
. | e | === - [10K] S -
. | |/ | | ^ | S ^
. +-| | | | | S |
. | |\ | PND | | | | |
. | c--------|>|---+---+----+ -+----+
. [Rb] | | |
. | | [Rc] |
. | | | |
. +------------------|--------------------+
. | | | |
. - | | |
. ^ [Rbc] c ON c
. | | |/ -- |/
. +-------+-|>|--+-| | | >-[Rb]-+-|
. | |\ | | | |\
. [Rp] e - - [Rp] e
. | | | |
. +---+----------------+---+
. |
. .---
. GND
.
.

Nah- what am I thinking- now the capacitor maintains a few 100mV forward
bias:
View in a fixed-width font such as Courier.

..
..
..
..
.. V+
.. | SD
.. +---+---+----|>|---+---+----------------+----+
.. | | | | | | |
.. [Rp] | | | + | | |
.. | e | === - S -
.. | |/ | | ^ S ^
.. +-| | | | S |
.. | |\ | PND | | | |
.. | c--------|>|---+---+--[10K]--|>|----+----+
.. [Rb] | | |
.. | | [Rc] |
.. | | | |
.. +------------------|--------------------+
.. | | | |
.. - | | |
.. ^ [Rbc] c ON c
.. | | |/ -- |/
.. +-------+-|>|--+-| | | >-[Rb]-+-|
.. | |\ | | | |\
.. [Rp] e - - [Rp] e
.. | | | |
.. +---+----------------+---+
.. |
.. .---
.. GND
..
..
 
E

ehsjr

Jan 1, 1970
0
Fred said:
Fred said:
Tony said:
I just noticed he said a *single* positive supply-"I have an app
where I am driving a solenoid using a dual op amp in bridge
configuration to double the effective voltage from a single
positive supply." So he's sunk. I can't even understand them
half the time- the basis for their question is so off-the-wall
they are unintelligible.




We've been here before Fred, a year or so ago.
A transient capacitive voltage doubler, generating
2xVs to pull the solenoid in, dropping back to 1xVs
for holding.

Maybe use a Schottky diode and linearizing resistor to bleed the few
nanoamps around the capacitor.
View in a fixed-width font such as Courier.


.
.
. V+
. | SD
. +---+---+----|>|---+---+----+-----------+----+
. | | | | | | | |
. [Rp] | | | + | | | |
. | e | === - [10K] S -
. | |/ | | ^ | S ^
. +-| | | | | S |
. | |\ | PND | | | | |
. | c--------|>|---+---+----+ -+----+
. [Rb] | | |
. | | [Rc] |
. | | | |
. +------------------|--------------------+
. | | | |
. - | | |
. ^ [Rbc] c ON c
. | | |/ -- |/
. +-------+-|>|--+-| | | >-[Rb]-+-|
. | |\ | | | |\
. [Rp] e - - [Rp] e
. | | | |
. +---+----------------+---+
. |
. .---
. GND
.
.

Nah- what am I thinking- now the capacitor maintains a few 100mV forward
bias:
View in a fixed-width font such as Courier.

.
.
.
.
. V+
. | SD
. +---+---+----|>|---+---+----------------+----+
. | | | | | | |
. [Rp] | | | + | | |
. | e | === - S -
. | |/ | | ^ S ^
. +-| | | | S |
. | |\ | PND | | | |
. | c--------|>|---+---+--[10K]--|>|----+----+
. [Rb] | | |
. | | [Rc] |
. | | | |
. +------------------|--------------------+
. | | | |
. - | | |
. ^ [Rbc] c ON c
. | | |/ -- |/
. +-------+-|>|--+-| | | >-[Rb]-+-|
. | |\ | | | |\
. [Rp] e - - [Rp] e
. | | | |
. +---+----------------+---+
. |
. .---
. GND
.
.

Geez, Fred, would you please make up Tony's mind? :)

Ed

P.S. Thanks for posting
 
T

Tony Williams

Jan 1, 1970
0
Or maybe it was this:
View in a fixed-width font such as Courier.

.
.
. V+
. |
. +---+----|>|----+------+-------+----+
. | | | | | |
. [Rp] | | + | | |
. | e === - S -
. | |/ | ^ S ^
. +-| | | S |
. | |\ | | | |
. | c-----------+------+ +----+
. [Rb] | |
. | | |
. | | |
. +---------------|--------------+
. | |
. | |
. ON [Rc] c
. -- | |/
. | | >--|-----[Rb]-+-|
. | | | | |\
. - - | [Rp] e
. | | |
. +----------+---+
. |
. .---
. GND
.
.

Similar to that one afair. Although it would be
nice for the pnp to go Off early to get longest
re-charge time for the C.
 
T

Tony Williams

Jan 1, 1970
0
Winfield Hill said:
Nice. I handed my technician a design for a box with ten
small microwave relays -- except the crazy relays want tight
connections I suppose, and each one takes 5W of coil power!
That's 50W for the set, and it's got me worried about heat.
I can't add a fan, because it's going on a quiet optics bench.
My tech's waiting for parts, so I've got a few days to improve
the coil-power scene.
Tony, did you come up with a slick circuit?

Fred seems to have it in hand. :)

I also recall on that thread a relay driver chip that
put full voltage on initially, then pwm'd to reduce
the relay power.
 
F

Fred Bloggs

Jan 1, 1970
0
Tony said:
Or maybe it was this:
View in a fixed-width font such as Courier.


.
.
. V+
. |
. +---+----|>|----+------+-------+----+
. | | | | | |
. [Rp] | | + | | |
. | e === - S -
. | |/ | ^ S ^
. +-| | | S |
. | |\ | | | |
. | c-----------+------+ +----+
. [Rb] | |
. | | |
. | | |
. +---------------|--------------+
. | |
. | |
. ON [Rc] c
. -- | |/
. | | >--|-----[Rb]-+-|
. | | | | |\
. - - | [Rp] e
. | | |
. +----------+---+
. |
. .---
. GND
.
.


Similar to that one afair. Although it would be
nice for the pnp to go Off early to get longest
re-charge time for the C.

Okay- then since the storage capacitor is not exactly a precision
component and can be oversized slightly, a one-shot based on worst case
solenoid pull-in time using low Vgs MOSFETs works- the sim looks good
for 2n7000's and 500mA @24V loads- can be scaled up if necessary:
View in a fixed-width font such as Courier.

..
..
.. +------------[Rg]----------+
.. | |
.. | V+ |
.. | | SD |
.. | +-------+----|>|-------+---+--------------+---+
.. | | | | | | |
.. | | | | + | | |
.. | d | C === - - S
.. | |-+ [Rb] S | ^ ^ S
.. +-|N | | | | S
.. | |-+ | | | | |
.. | s----------------------+---+ +---+
.. | | | |
.. c | | |
.. \| | | |
.. |--+--|<|-+----||-------------------------------+
.. /| | C | |
.. e [Rp] T | ON |
.. | | | -- d
.. | | [Rc] | | |-+
.. | | | | | >-[Rg]-+-|N
.. | | | - - | |-+
.. | | | [Rp] s
.. | | | | |
.. +----+---------------------+------------------+---+
.. |
.. ---
.. GND
..
..
 
F

Fred Bartoli

Jan 1, 1970
0
Tony Williams said:
Fred seems to have it in hand. :)

I also recall on that thread a relay driver chip that
put full voltage on initially, then pwm'd to reduce
the relay power.

I remember doing that with a 555 in the 80s.

If one have enough relays to justify 2 supply voltages and don't want high
toggle rate, then this simple one will do:


Vsust -------------.
|
|
C|
C|
C|
|
|
,-----+
| |
V ---
- ===
| +| ___
`-----+---|___|--> Vstart > Vsust
|
|
||-+
||<-
---||-+
|
===
GND
 
F

Fred Bloggs

Jan 1, 1970
0
Tony said:
Or maybe it was this:
View in a fixed-width font such as Courier.


.
.
. V+
. |
. +---+----|>|----+------+-------+----+
. | | | | | |
. [Rp] | | + | | |
. | e === - S -
. | |/ | ^ S ^
. +-| | | S |
. | |\ | | | |
. | c-----------+------+ +----+
. [Rb] | |
. | | |
. | | |
. +---------------|--------------+
. | |
. | |
. ON [Rc] c
. -- | |/
. | | >--|-----[Rb]-+-|
. | | | | |\
. - - | [Rp] e
. | | |
. +----------+---+
. |
. .---
. GND
.
.


Similar to that one afair. Although it would be
nice for the pnp to go Off early to get longest
re-charge time for the C.

I suppose this could be made into a real workhorse:
View in a fixed-width font such as Courier.

..
.. +----------------------------------+
.. | |
.. | |
.. e |
.. \| |
.. |---------------------+---[Rp]---+
.. /| | |
.. c | |
.. | V+ | |
.. | | SD | |
.. | +-----|>|---------------+----+---------+
.. [100] | | | | |
.. | | | | | |
.. | d | | | +---+
.. | |-+ | | + | | |
.. +--------|N [Rbg] C === - - S
.. | |-+ | S | ^ ^ S
.. | s | | | | S
.. | | | | | | |
.. | | | | | +---+
.. | SD | | | | |
.. +-|<|-[10]-+-----------------------+----+ |
.. | | |
.. | | |
.. d | |
.. +-| | |
.. N|---------------------+--------||---------------+
.. +-| C |
.. s T ON |
.. | -- d
.. | | | |-+
.. | | | >--+-|N
.. | - - | |-+
.. | [Rp] s
.. | | |
.. +--------------------------+------------------+---+
.. |
.. ---
.. GND
..
 
F

Fred Bloggs

Jan 1, 1970
0
Some clamp diodes:
View in a fixed-width font such as Courier.

..
.. +----------------------------------+
.. | |
.. e |
.. \| |
.. |---------------------+---[Rp]---+
.. /| | |
.. c | |
.. | +---|>|----+
.. | V+ | |
.. | | SD | |
.. | +----+--|>|-------------+----+---------+
.. [100] | | | | | |
.. | | | | | | |
.. | d | | | | +---+
.. | |-+ | | | + | | |
.. +--------|N - [Rbg] C === - - S
.. | |-+ ^ | S | ^ ^ S
.. | s | | | | | S
.. | | | | | | | |
.. | | | | | | +---+
.. | SD | | | | | |
.. +-|<|-[10]-+-----------------------+----+ |
.. | | | |
.. | | | |
.. d | | |
.. +-| | | + |
.. N|-------------+-------+--------||---------------+
.. +-| C |
.. s T ON |
.. | -- d
.. | | | |-+
.. | | | >--+-|N
.. | - - | |-+
.. | [Rp] s
.. | | |
.. +--------------------------+------------------+---+
.. |
.. ---
.. GND
..
 
F

Fred Bloggs

Jan 1, 1970
0
Tony said:
Or maybe it was this:
View in a fixed-width font such as Courier.



.
.
. V+
. |
. +---+----|>|----+------+-------+----+
. | | | | | |
. [Rp] | | + | | |
. | e === - S -
. | |/ | ^ S ^
. +-| | | S |
. | |\ | | | |
. | c-----------+------+ +----+
. [Rb] | |
. | | |
. | | |
. +---------------|--------------+
. | |
. | |
. ON [Rc] c
. -- | |/
. | | >--|-----[Rb]-+-|
. | | | | |\
. - - | [Rp] e
. | | |
. +----------+---+
. |
. .---
. GND
.
.


Similar to that one afair. Although it would be
nice for the pnp to go Off early to get longest
re-charge time for the C.
I suppose this could be made into a real workhorse:
View in a fixed-width font such as Courier.

..
.. +----------------------------------+
.. | |
.. | |
.. e |
.. \| |
.. |---------------------+---[Rp]---+
.. /| | |
.. c | |
.. | V+ | |
.. | | SD | |
.. | +-----|>|---------------+----+---------+
.. [100] | | | | |
.. | | | | | |
.. | d | | | +---+
.. | |-+ | | + | | |
.. +--------|N [Rbg] C === - - S
.. | |-+ | S | ^ ^ S
.. | s | | | | S
.. | | | | | | |
.. | | | | | +---+
.. | SD | | | | |
.. +-|<|-[10]-+-----------------------+----+ |
.. | | |
.. | | |
.. d | |
.. +-| | |
.. N|---------------------+--------||---------------+
.. +-| C |
.. s T ON |
.. | -- d
.. | | | |-+
.. | | | >--+-|N
.. | - - | |-+
.. | [Rp] s
.. | | |
.. +--------------------------+------------------+---+
.. |
.. ---
.. GND
..
 
F

Fred Bloggs

Jan 1, 1970
0
Some clamp diodes:
View in a fixed-width font such as Courier.

..
.. +----------------------------------+
.. | |
.. e |
.. \| |
.. |---------------------+---[Rp]---+
.. /| | |
.. c | |
.. | +---|>|----+
.. | V+ | |
.. | | SD | |
.. | +----+--|>|-------------+----+---------+
.. [100] | | | | | |
.. | | | | | | |
.. | d | | | | +---+
.. | |-+ | | | + | | |
.. +--------|N - [Rbg] C === - - S
.. | |-+ ^ | S | ^ ^ S
.. | s | | | | | S
.. | | | | | | | |
.. | | | | | | +---+
.. | SD | | | | | |
.. +-|<|-[10]-+-----------------------+----+ |
.. | | | |
.. | | | |
.. d | | |
.. +-| | | + |
.. N|-------------+-------+--------||---------------+
.. +-| C |
.. s T ON |
.. | -- d
.. | | | |-+
.. | | | >--+-|N
.. | - - | |-+
.. | [Rp] s
.. | | |
.. +--------------------------+------------------+---+
.. |
.. ---
.. GND
..
 
H

Harry Dellamano

Jan 1, 1970
0
Fred Bloggs said:
Some clamp diodes:
View in a fixed-width font such as Courier.

.
. +----------------------------------+
. | |
. e |
. \| |
. |---------------------+---[Rp]---+
. /| | |
. c | |
. | +---|>|----+
. | V+ | |
. | | SD | |
. | +----+--|>|-------------+----+---------+
. [100] | | | | | |
. | | | | | | |
. | d | | | | +---+
. | |-+ | | | + | | |
. +--------|N - [Rbg] C === - - S
. | |-+ ^ | S | ^ ^ S
. | s | | | | | S
. | | | | | | | |
. | | | | | | +---+
. | SD | | | | | |
. +-|<|-[10]-+-----------------------+----+ |
. | | | |
. | | | |
. d | | |
. +-| | | + |
. N|-------------+-------+--------||---------------+
. +-| C |
. s T ON |
. | -- d
. | | | |-+
. | | | >--+-|N
. | - - | |-+
. | [Rp] s
. | | |
. +--------------------------+------------------+---+
. |
. ---
. GND
.

Hey FB
You should get a job as a field apps. engineer for a semi house. They love
circuits with lots of semis.
You had it optimized way back when, just change Rb to a cap to turn off the
high side driver for quicker recharge. In that older circuit, I changed the
high side PNP to a PMOS and low side NPN to a NMOS, added high side turn off
cap and filed it away.
Cheers,
Harry
 
F

Fred Bloggs

Jan 1, 1970
0
Harry said:
Hey FB
You should get a job as a field apps. engineer for a semi house. They love
circuits with lots of semis.
You had it optimized way back when, just change Rb to a cap to turn off the
high side driver for quicker recharge. In that older circuit, I changed the
high side PNP to a PMOS and low side NPN to a NMOS, added high side turn off
cap and filed it away.
Cheers,
Harry

I suppose that will do most of the time but this thing evolved into
three main goals:
o super-low RDS,ON N-MOSFETs throughout,
o zero OFF state current,
o crowbar re-charging of the storage capacitor.

That capacitor coupling into the MOSFET for long timeouts is way too
slow at turn-off. I can't get zero OFF state current, but the 100u of
the LMC555 is close enough- so this circuit is low stress on the
components, and does the job:
View in a fixed-width font such as Courier.

..
.. +----------------------------------+
.. | |
.. e |
.. \| |
.. 2N4403 |--------------+----------[1K]---+
.. /| | |
.. c | |
.. | | |
.. | 12V c 2N4401 |
.. | | |/ SD |
.. | +---+-----------+---|>|-+----+---------+
.. [100] | |\ | | | |
.. | | e | | | |
.. | d | | | | +---+
.. | |-+ | | | + | | |
.. +--------|N [1K] | C === - - S
.. | |-+ | | S | ^ ^ S
.. | s | | | | | S
.. | | | | | | | |
.. | | | | | | +---+
.. | SD | | | | | |
.. +-|<|-[1]--+-----------------------+----+ |
.. | | | |
.. | | | ON |
.. d | +---------+ -- |
.. +-| | | V+/RST | | | >---+ |
.. N|--------------+ | | | | | |
.. +-| | | | - - | |
.. s | | | | |
.. | +--|<|---+----|OUT THR|---+--||-----+ |
.. | | |_ | | | 1n | |
.. | | |/| | LMC555 | | | |
.. | | [pot] | | +---+ | |
.. | | /| | | | | | |
.. | +-[1K]---+----|TRG | [10K] | | d
.. | |+ | | | | | |-+
.. | === | GND | | - +-|N
.. | |C +---------+ | ^ | |-+
.. | | T | | | [Rp] s
.. | | | | | | |
.. +----------------+---------+--------+---+-----+---+
.. |
.. ---
.. GND
..
..
 
F

Fred Bloggs

Jan 1, 1970
0
Whoops- just spotted an opportunity to add two more diodes:)
View in a fixed-width font such as Courier.

..
..
.. +----------------------------------+
.. | |
.. e 2N4403 |
.. \| |
.. |--------------+----------[1K]---+
.. /| | |
.. c 12V | |
.. | | | SD |
.. | +---------------+---|>|-+----+---------+
.. | | | | | | |
.. [100] | | - | | |
.. | | | v | | |
.. | d | | | | +---+
.. | |-+ c - | + | | |
.. +--------|N \| v C === - - S
.. | |-+ |-------+ S | ^ ^ S
.. | s /| | | | | S
.. | | e | | | | |
.. | | |2N4401 | | | +---+
.. | SD | | | | | |
.. +-|<|-[1]--+-----------------------+----+ |
.. | | | |
.. | | | ON |
.. d [1K] +---------+ -- |
.. +-| | | V+/RST | | | >---+ |
.. N|--------------+ | | | | | |
.. +-| | | | - - | |
.. s | | | | |
.. | +--|<|---+----|OUT THR|---+--||-----+ |
.. | | |_ | | | 1n | |
.. | | |/| | LMC555 | | | |
.. | | [pot] | | +---+ | |
.. | | /| | | | | | |
.. | +-[1K]---+----|TRG | [10K] | | d
.. | |+ | | | | | |-+
.. | === | GND | | - +-|N
.. | |C +---------+ | ^ | |-+
.. | | T | | | [Rp] s
.. | | | | | | |
.. +----------------+---------+--------+---+-----+---+
.. |
.. ---
.. GND
..
..
 
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