| View previous topic :: View next topic |
| Author |
Message |
Eeyore
Guest
|
 Posted: Sun Oct 26, 2008 7:27 am Post subject: Re: Question about transistor breakdown voltage |
 |
|
Jasen Betts wrote:
[quote]On 2008-10-23, Gerbermultit00l@gmail.com <Gerbermultit00l@gmail.com> wrote:
On Oct 23, 2:20Â pm, "pimpom" <pim...@invalid.invalid> wrote:
The darlington transistor is an NPN device used as a low side switch.
Emitter is tied to ground. I am interested in understanding what
happens when the collector goes negative with respect to ground.
what>s connected to the base?
[/quote]
A fairie. |
|
| |
|
 Back to top |
Eeyore
Guest
|
| Posted: Sun Oct 26, 2008 7:27 am Post subject: Re: Question about transistor breakdown voltage |
|
|
Gerbermultit00l@gmail.com wrote:
[quote]I am interested in understanding what
happens when the collector goes negative with respect to ground.
[/quote]
And why would that happen ?
Never heard of inverse parallel diodes ?
Graham |
|
| |
|
| Back to top |
Eeyore
Guest
|
| Posted: Sun Oct 26, 2008 7:27 am Post subject: Re: Question about transistor breakdown voltage |
|
|
Gerbermultit00l@gmail.com wrote:
[quote]I see in the specification sheet for a darlington transistor that its
collector to emitter breakdown voltage is 100V.
[/quote]
Vceo, Vceb or Vcev ?
Graham |
|
| |
|
| Back to top |
pimpom
Guest
|
| Posted: Sun Oct 26, 2008 5:41 pm Post subject: Re: Max ratings of electret mic |
|
|
"Phil Allison" <philallison@tpg.com.au> wrote in message
news:6mhqeaFgrrd9U1@mid.individual.net...
[quote]
"pimpom"
** Get fucked you vile little shit.
Oh, I do. All the time. OTOH, how long has it been since you got[/quote]
laid - not couning those desperate homo sessions? A year?
You can congratulate yourself on one thing, though. Although
you>re only the third person I>ve ever flamed over the internet,
you>re the very first on whom I>ve ever used vulgar language. You
must have caught me in a good mood. Congratulations. |
|
| |
|
| Back to top |
John Fields
Guest
|
| Posted: Sun Oct 26, 2008 8:52 pm Post subject: Re: Question about transistor breakdown voltage |
|
|
On Sat, 25 Oct 2008 14:30:41 -0700, Dr. Polemic <nospam@aol.com> wrote:
[quote]On Sat, 25 Oct 2008 11:52:20 -0500, John Fields
jfields@austininstruments.com> wrote:
On Sat, 25 Oct 2008 09:05:31 -0700, Dr. Polemic <nospam@aol.com> wrote:
On Fri, 24 Oct 2008 09:10:40 -0500, John Fields
jfields@austininstruments.com> wrote:
On Fri, 24 Oct 2008 11:35:38 +1100, "Phil Allison"
philallison@tpg.com.au> wrote:
Gerbermultit00l@gmail.com
I see in the specification sheet for a darlington transistor that its
collector to emitter breakdown voltage is 100V.
What is its emitter to collector breakdown voltage?
** Look at the diagram of the darlington - see a diode drawn from
collector to emitter?
All power darlingtons have them.
Means full conduction from 0.6 volts when subjected to reverse polarity.
---
Phil 1, everyone else 0.
Apparently not.
---
OK.
Phil 1000, you 1
Given Phil>s normal tendency to mercilessly rag on anyone who makes any
assumption that he considers unwarranted, he must be held to his own high
standard in that respect. Since the OP didn>t use the word "power" in any
of his posts, Phil gets 0, not 1000, a forfeit for bad behavior.
[/quote]
---
Perhaps the OP will come forward with the device he was referring to and
end the squabbling?
JF |
|
| |
|
| Back to top |
Robert Monsen
Guest
|
| Posted: Mon Oct 27, 2008 7:15 am Post subject: Re: Audio amplifier (part 2) |
|
|
On Fri, 24 Oct 2008 08:10:56 -0500, John Fields
<jfields@austininstruments.com> wrote:
[quote]On Fri, 24 Oct 2008 11:26:45 +0200, Olivier Scalbert
olivier.scalbert@algosyn.com> wrote:
Olivier Scalbert wrote:
John Fields wrote:
I haven>t found out how to do an FFT in LTspice yet, so there may be an
itermodulation problem lurking in there somewhere.
JF
Hi John,
For the FFT, just right click in the simulation screen and select FFT in
the popup menu.
Olivier
Also increase stop time in the simulation box to have more points.
---
OK, thanks.
---
BTW how to convert harmonic levels in FFT to distorsion in percentage ?
---
http://en.wikipedia.org/wiki/Total_harmonic_distortion
JF
[/quote]
You can also insert a .FOUR directive, which will compute it for you
and write a table into the error log
..FOUR <Freq> <Node>
There are other options. See the 'help' for more info.
Regards,
Bob Monsen |
|
| |
|
| Back to top |
Olivier Scalbert
Guest
|
| Posted: Mon Oct 27, 2008 1:19 pm Post subject: Re: Audio amplifier (part 2) |
|
|
John Fields wrote:
[quote]Empirically. ;)
In the simulator, what I did was (with 0V into R1) arbitrarily choose R6
and R8 at 1000 ohms and then adjusted R4 and R5 for 30mA of current
through both MOSFETs.
In the real world, what I>d do would be to replace the resistors with
1000 ohm pots, like this: (View in Courier)
+----------------------------+
| |
+V>---------------------|---+----------+-------+ |
| | | | |
| | | D |
[510] | [POT]<--G NCH |
| | | S |
| | [DIODE] | |
VIN>-------------[100]--+--|-\ |K | |
| >--------+ +-----+
+--|+/ |A | |
| | [DIODE] | [LOAD]
[82] | | S |
| | [POT]<--G PCH GND
GND | | D
| | |
-V>-------------------------+----------+-------+
Then, before applying power I>d make sure Vin was grounded and the pots
were cranked to zero ohms between the gates and the diodes.
After that, I>d apply power and crank one of the pots until I got 30mA
through the load and then crank the other pot until the current through
the load fell to zero.
That 30 mA will now be in both MOSFETs and will be the current causing
the stage to run AB which will kill crossover distortion. Also, the
load will be DC coupled to the input and will be at zero volts with zero
volts on Vin, which is what you want.
There also probably needs to be some soft-start circuitry in there
somewhere to protect the load and the MOSFETS against power-on
transients from the opamp. Something as simple as a relay momentarily
shorting the opamp>s output to ground during power-on should work:
+V-----+--------+------+ NC
| | | |<-O------+
| [DIODE] [COIL]- - -| |
[R] |A | C O |
| +------+ | |+\ |
| | | | >--+-->TO DIODES
| C | |-/
+------B |
| E |
[C] | |
| | |
GND>---+--------+---------------+
JF
[/quote]
Thnaks for the info John !
Olivier |
|
| |
|
| Back to top |
Robert Monsen
Guest
|
| Posted: Tue Oct 28, 2008 7:14 am Post subject: Re: About Radio Waves |
|
|
On Thu, 23 Oct 2008 18:40:38 GMT, Rich Grise <rich@example.net> wrote:
[quote]On Thu, 23 Oct 2008 02:48:12 -0700, jaiprakash.788 wrote:
How can we make a Radio transmitter and receiver. Pl. give me some easiest
possible ways to do so.
Easiest way I know of:
http://www.radioshack.com/product/index.jsp?productId=3198210&cp=&sr=1&kw=remote+switch&origkw=remote+switch&parentPage=search
(or you could go to the other side of google and search for "radio
tutorial".)
Cheers!
Rich
[/quote]
I just saw a wireless light switch for $15 at Fry>s. You can>t buy the
wireless tx/rx for that from the surplus places. So, buy one, and tear
it apart to get the parts. You>ll also get a nice relay and switch.
If you are in India, you can probably get one for 500 rupees...
Regards,
Bob Monsen |
|
| |
|
| Back to top |
whit3rd
Guest
|
| Posted: Wed Oct 29, 2008 5:26 pm Post subject: Re: high current charge pump |
|
|
On Oct 21, 12:22 pm, mrdarr...@gmail.com wrote:
[quote]Typical pump drivers seem limited to a few dozen mA.
Do any charge pump drivers exist which can convert 12VDC to +/- 24VDC
at ~ 2A?
[/quote]
Most of these 'charge pump' devices are switch/capacitor devices,
and the power efficiency is poor (under 50% of input power is
delivered to the load).
If your output is to be 2A at +/- 24VDC, that>s 100W; use a
switchmode DC/DC converter, with transformer, for that kind
of application. |
|
| |
|
| Back to top |
fine
Guest
|
| Posted: Sun Nov 02, 2008 11:01 am Post subject: Re: Bape shoes |
|
|
please look our website ,have more mode shoes clothing hat cap bags !
Dsquared 2 shoes,Dsquared jeans t-shirt Dsquared jacket www.shoestrade.biz
A&F Abercrombie & Fitch t-shirt bags jeans jacket apparel www.shoestrade.biz
air max 90 shoes 87 88 89 ltd 91 95 97 tn shoes www.shoestrade.biz
shox Nz R5 r4 r3 r2 tl Energia Rival Classic shoes www.shoestrade.biz
dunk sb shoes hogan shoes air rift shoes puma shoes www.shoestrade.biz
Timberland boots prada shoes Gucci shoes d&g shoes www.shoestrade.biz
Discount UGG Boots china usa Australia www.shoestrade.biz
Adidas shoes adidas city adidas 35 years adidas good year shoes
www.shoestrade.biz
Jordans shoes BAPE STA Shoes Converse shoes Lacoste shoes www.shoestrade.biz
Air force one shoes air force one 25 yars shoes www.shoestrade.biz
IPhone NOKIA VERTU NOKIA N96 N95 8800 Sirocco 8800 Sapphire Arte
WWW.SHOESTRADE.BIZ
Ipod MP3 MP4 MP5 ipod touch Glasses MP3 SONY PSP PS3 WWW.SHOESTRADE.BIZ
LV Bag Gucci Bag Chanel Bag D&G Bag Chloe Bag Feidi Bag WWW.SHOESTRADE.BIZ
Guess Bag Coach Bag Juicy Bag Prada Bag BULL Bag WWW.SHOESTRADE.BIZ
Burberry Bag Versace Bag Dooney&Bourke Bag Jimmy Choo Bag WWW.SHOESTRADE.BIZ
Dior Bag Loewe Bag ED HARDY Bag HERMES Bag TOUS Bag WWW.SHOESTRADE.BIZ
ARMANI T-shirt ARMANI jeans ARMANI jacket ARMANI bags WWW.SHOESTRADE.BIZ
Dolce&Gabbana d&g lei>s T-shirt jeans jacket d&g bags WWW.SHOESTRADE.BIZ
CA AFF bape ggg g-star T-shirt jeans jacket hood WWW.SHOESTRADE.BIZ
Polo lacoste T-shirt jacket hood gucci shoes WWW.SHOESTRADE.BIZ
ED HARDY T-shirt jacket hood Bag gucci shoes WWW.SHOESTRADE.BIZ
BAPE STAR BAPE STA SHOES T-SHIRT HOOD JACJET JEANS WWW.SHOESTRADE.BIZ
Air Max
Air Max 87 shoes www.shoestrade.biz
Air Max 90 shoes www.shoestrade.biz
Air Max 91 shoes www.shoestrade.biz
Air Max 93 shoes www.shoestrade.biz
Air Max 95 shoes www.shoestrade.biz
Air Max 97 shoes www.shoestrade.biz
Air Max 2003 shoes www.shoestrade.biz
Air Max 360 shoes www.shoestrade.biz
Air Max 180 shoes www.shoestrade.biz
Air Max TN shoes www.shoestrade.biz
Air Max TN2 shoes www.shoestrade.biz
Air Max TN3 shoes www.shoestrade.biz
Air Max TN6 shoes www.shoestrade.biz
Air Max TN8 shoes www.shoestrade.biz
Air Max LTD shoes www.shoestrade.biz
Air Max 1 id shoes www.shoestrade.biz
Shox
Shox NZ shoes www.shoestrade168.cn
Shox R4 shoes www.shoestrade168.cn
Shox R2 shoes www.shoestrade168.cn
Shox R3 shoes www.shoestrade168.cn
Shox TL3 shoes www.shoestrade168.cn
Shox TL4 shoes www.shoestrade168.cn
Shox TL shoes www.shoestrade168.cn
Shox OZ shoes www.shoestrade168.cn
Shox Rival shoes www.shoestrade168.cn
Shox Classic shoes www.shoestrade168.cn
Shox Energia shoes www.shoestrade168.cn
sony PSP sp2 ps3
MP3 MP4 www.shoestrade168.cn
ipod nano 3 8gb 16gb 32gb
ipod touch www.shoestrade168.cn
Mobile phone www.shoestrade168.cn
iPhone 8gb 16gb www.shoestrade168.cn
nokia 8800 www.shoestrade168.cn
nokia 8800 Sirocco www.shoestrade168.cn
nokia 8800 Sapphire Arte www.shoestrade168.cn
nokia n95 8gb www.shoestrade168.cn
nokia n93i www.shoestrade168.cn
nokia n73 www.shoestrade168.cn
nokia n96 www.shoestrade168.cn
NOKIA 5700 www.shoestrade168.cn
NOKIA 6300 www.shoestrade168.cn
Nokia 7500 www.shoestrade168.cn
NOKIA N76 www.shoestrade168.cn
NOKIA N77 www.shoestrade168.cn
NOKIA N81 www.shoestrade168.cn
NOKIA N800 www.shoestrade168.cn
NOKIA e90 www.shoestrade168.cn
NOKIA N77 www.shoestrade168.cn
NOKIA N92 www.shoestrade168.cn
NOKIA N8600 www.shoestrade168.cn
NOKIA AEON www.shoestrade168.cn
CECT www.shoestrade168.cn
VERTU www.shoestrade168.cn
dopod www.shoestrade168.cn
iPhone 16gb www.shoestrade168.cn
MOTO 1200 www.shoestrade168.cn
www.shoestrade.biz |
|
| |
|
| Back to top |
Olivier Scalbert
Guest
|
| Posted: Mon Nov 03, 2008 7:36 pm Post subject: Re: Audio amplifier (part 2) |
|
|
John Fields wrote:
[quote]Empirically. ;)
In the simulator, what I did was (with 0V into R1) arbitrarily choose R6
and R8 at 1000 ohms and then adjusted R4 and R5 for 30mA of current
through both MOSFETs.
In the real world, what I>d do would be to replace the resistors with
1000 ohm pots, like this: (View in Courier)
+----------------------------+
| |
+V>---------------------|---+----------+-------+ |
| | | | |
| | | D |
[510] | [POT]<--G NCH |
| | | S |
| | [DIODE] | |
VIN>-------------[100]--+--|-\ |K | |
| >--------+ +-----+
+--|+/ |A | |
| | [DIODE] | [LOAD]
[82] | | S |
| | [POT]<--G PCH GND
GND | | D
| | |
-V>-------------------------+----------+-------+
Then, before applying power I>d make sure Vin was grounded and the pots
were cranked to zero ohms between the gates and the diodes.
After that, I>d apply power and crank one of the pots until I got 30mA
through the load and then crank the other pot until the current through
the load fell to zero.
That 30 mA will now be in both MOSFETs and will be the current causing
the stage to run AB which will kill crossover distortion. Also, the
load will be DC coupled to the input and will be at zero volts with zero
volts on Vin, which is what you want.
There also probably needs to be some soft-start circuitry in there
somewhere to protect the load and the MOSFETS against power-on
transients from the opamp. Something as simple as a relay momentarily
shorting the opamp>s output to ground during power-on should work:
+V-----+--------+------+ NC
| | | |<-O------+
| [DIODE] [COIL]- - -| |
[R] |A | C O |
| +------+ | |+\ |
| | | | >--+-->TO DIODES
| C | |-/
+------B |
| E |
[C] | |
| | |
GND>---+--------+---------------+
JF
[/quote]
Hi JF,
If I build it in real, how can I measure the current in the MOSFETS ?
Should I put small resitors in the sources (or drains) ?
Olivier |
|
| |
|
| Back to top |
John Fields
Guest
|
| Posted: Mon Nov 03, 2008 8:21 pm Post subject: Re: Audio amplifier (part 2) |
|
|
On Mon, 03 Nov 2008 14:36:39 +0100, Olivier Scalbert
<olivier.scalbert@algosyn.com> wrote:
[quote]John Fields wrote:
Empirically. ;)
In the simulator, what I did was (with 0V into R1) arbitrarily choose R6
and R8 at 1000 ohms and then adjusted R4 and R5 for 30mA of current
through both MOSFETs.
In the real world, what I>d do would be to replace the resistors with
1000 ohm pots, like this: (View in Courier)
+----------------------------+
| |
+V>---------------------|---+----------+-------+ |
| | | | |
| | | D |
[510] | [POT]<--G NCH |
| | | S |
| | [DIODE] | |
VIN>-------------[100]--+--|-\ |K | |
| >--------+ +-----+
+--|+/ |A | |
| | [DIODE] | [LOAD]
[82] | | S |
| | [POT]<--G PCH GND
GND | | D
| | |
-V>-------------------------+----------+-------+
Then, before applying power I>d make sure Vin was grounded and the pots
were cranked to zero ohms between the gates and the diodes.
After that, I>d apply power and crank one of the pots until I got 30mA
through the load and then crank the other pot until the current through
the load fell to zero.
That 30 mA will now be in both MOSFETs and will be the current causing
the stage to run AB which will kill crossover distortion. Also, the
load will be DC coupled to the input and will be at zero volts with zero
volts on Vin, which is what you want.
There also probably needs to be some soft-start circuitry in there
somewhere to protect the load and the MOSFETS against power-on
transients from the opamp. Something as simple as a relay momentarily
shorting the opamp>s output to ground during power-on should work:
+V-----+--------+------+ NC
| | | |<-O------+
| [DIODE] [COIL]- - -| |
[R] |A | C O |
| +------+ | |+\ |
| | | | >--+-->TO DIODES
| C | |-/
+------B |
| E |
[C] | |
| | |
GND>---+--------+---------------+
JF
Hi JF,
If I build it in real, how can I measure the current in the MOSFETS ?
Should I put small resitors in the sources (or drains) ?
[/quote]
---
No, just use the voltage dropped across the load to calculate the
current.
For 30mA into 8 ohms, say, you>d have:
E = IR = 0.03A * 8R = 0.240 volts
Then, before applying power make sure Vin is grounded and the pots
are cranked to zero ohms between the gates and the diodes.
After that, apply power and crank one of the pots until there>s 240mV
across the load. Then crank the other pot until the voltage across
the load falls to zero, and you>re done.
JF |
|
| |
|
| Back to top |
JosephKK
Guest
|
| Posted: Tue Nov 04, 2008 8:17 am Post subject: Re: Want to build a HEI ignition module similar to 70>s sty |
|
|
On Tue, 23 Sep 2008 15:26:42 -0400, default <default@defaulter.net>
wrote:
[quote]Does anyone have a schematic for a simple four pin HEI ignition module
from 1970>s+ ignition systems. They appear to contain an SCR and a
pair of diodes and resistors.
Pickup Coil connects to two terminals and battery and induction coil
primary the other two, mounting screw provides a ground connection.
Original type mounted to the distributor plate on GM cars and others
and was ~1/4 round shape - I want to adapt it to a motorcycle that has
pickup coils mounted remote from the modules.
[/quote]
Whatever you do, it will be specific to that make, model and year. Do
you know that most 4-cylinder MC have two ignition coils (and no
distributor)? (Some have 4, and many V-twins have two.) Many 1970s
and later MC have some variation of CDI already, do you know what it
currently has? What kind of sensor coils does it use (some still used
points)? Does it have speed variable timing, some do, and some don>t. |
|
| |
|
| Back to top |
Olivier Scalbert
Guest
|
| Posted: Wed Nov 05, 2008 12:40 am Post subject: Re: Audio amplifier (part 2) |
|
|
John Fields wrote:
[quote]Not necessarily.
As John Popelish noted, using negative feedback and providing a little
bias when the input is at zero volts will force the output to be at zero
volts during those times.
Run this to see how it could be done:
Version 4
SHEET 1 1476 680
JF
[/quote]
I still have a question ...
Gain is R3/R4.
If I want to increase the gain let say to 10, is it better to increase
R3/R4 or put an other amp-op as preamp in front ?
Olivier |
|
| |
|
| Back to top |
John Fields
Guest
|
| Posted: Wed Nov 05, 2008 3:58 am Post subject: Re: Audio amplifier (part 2) |
|
|
On Tue, 04 Nov 2008 19:40:12 +0100, Olivier Scalbert
<olivier.scalbert@algosyn.com> wrote:
[quote]John Fields wrote:
Not necessarily.
As John Popelish noted, using negative feedback and providing a little
bias when the input is at zero volts will force the output to be at zero
volts during those times.
Run this to see how it could be done:
Version 4
SHEET 1 1476 680
JF
I still have a question ...
Gain is R3/R4.
If I want to increase the gain let say to 10, is it better to increase
R3/R4 or put an other amp-op as preamp in front ?
[/quote]
---
R3/R4 sounds funny; on my LTspice schematic it>s R3/R2.
Anyway, whatever the reference designations are, here>s how it should be
with the gain set to 10 by R2/R1.
+----------------------------+
| |
+V>---------------------|---+----------+-------+ |
| | | | |
| | |1K D |
R2[1000] | R4 [POT]<--G NCH |
| | | S Q1 |
R1 | | CR1[1N4148] | |
VIN>-------------[100]--+--|-\ |K | |
| >--------+ +-----+
+--|+/ |A | |
| | CR2[1N4148] | [LOAD]
R3[91] | | S |
| | R5 [POT]<--G PCH GND
GND | |1K D Q2
| | |
-V>-------------------------+----------+-------+
JF |
|
| |
|
| Back to top |
|
