On 27 Sep 2006 03:05:16 -0700, "Telstar Electronics"
wrote in
om:

Frank Gilliland wrote:
http://www.ifwtech.co.uk/g3sek/tr-bias/tr-bias1.htm

Thanks Frank for posting this link.


No problem.


It supports what I've been saying
all along about the plain-old diode method working like crap.


The diode method works, it's just not idiot-proof so it's no good for
a production CB amp. So why didn't you incorporate the concept in your
earlier amps instead of vehemently defending your no-bias Class C POS
by claiming that "linearity is not required for SSB"?


So why
don't you go ahead and use that method on your new amp... LOL


Naw, I have a better system.

Frank Gilliland wrote:
The diode method works, it's just not idiot-proof so it's no good for
a production CB amp.

Well, I claim it doesn't work... unless you want to tell me how you can
parallel two diodes together... without any ballasting... and have both
of them turned on. That's essentially what that circuit is doing.
Unlike you... I have certainly tried it before. It doesn't work... for
the reason I stated.

http://search.ebay.com/_W0QQfgtpZ1QQ...Q2delectronics

On 27 Sep 2006 04:42:20 -0700, "Telstar Electronics"
wrote in
om:


Frank Gilliland wrote:
The diode method works, it's just not idiot-proof so it's no good for
a production CB amp.

Well, I claim it doesn't work... unless you want to tell me how you can
parallel two diodes together... without any ballasting... and have both
of them turned on. That's essentially what that circuit is doing.


No, it's not. I explained this before but apparently it flew over your
head. So I'll try to make it a bit simpler for you: Instead of having
a single diode checking the heat of two transistors, this guy used one
diode on -each- transistor. They may be wired in parallel but they are
-not- expected to work at the same time. Why? Because the bias will be
fixed by the diode with the lowest Vf, which will be the hotter of the
two diodes (Vf decreases as temperature increases).


Unlike you... I have certainly tried it before. It doesn't work... for
the reason I stated.


Well Brian, I -have- used the circuit before, in several different
variations, and yes it -does- work.

Frank Gilliland wrote:
Well Brian, I -have- used the circuit before, in several different
variations, and yes it -does- work.

Then show me the circuit that worked.

http://search.ebay.com/_W0QQfgtpZ1QQ...Q2delectronics

On Wed, 27 Sep 2006 05:10:56 -0700, Frank Gilliland
wrote in
:

On 27 Sep 2006 04:42:20 -0700, "Telstar Electronics"
wrote in
. com:


Frank Gilliland wrote:
The diode method works, it's just not idiot-proof so it's no good for
a production CB amp.

Well, I claim it doesn't work... unless you want to tell me how you can
parallel two diodes together...


Guess what, Brian? I took a closer look at the pic and it turns out
the diodes are IN SERIES! Doesn't matter tho, because as I was
browsing the other photos it appears that the amp has a seperate bias
regulator circuit that was added and is controlled by the Vf of the
two diodes in series, which is an even better method.

On 27 Sep 2006 05:38:27 -0700, "Telstar Electronics"
wrote in
om:

Frank Gilliland wrote:
Well Brian, I -have- used the circuit before, in several different
variations, and yes it -does- work.

Then show me the circuit that worked.


Regarding the parallel circuit, I'll save myself the effort of digging
the scanner out of the closet; Here are a couple literary references
from my bookshelf that you can probably dig up at your local library.
Both of them have circuits that utilize the same parallel arrangement
in one form or another:

Motorola Power Transistor Handbook, 1961 (and probably other years)
(see section on power inverters)

Electronic Circuit Design Handbook, EEE Magazine, 1971-74 (several
different circuits in various sections)

If you can't find those books, can't find any references yourself, and
can't figure out how to set up a simple test circuit to verify its
operation, let me know in a month or so when the weather goes sour and
I'll have more time to spend on your education.

wrote in
Then show me the circuit that worked.


Frank Gilliland wrote:
Regarding the parallel circuit, I'll save myself the effort of digging
the scanner out of the closet; Here are a couple literary references
from my bookshelf that you can probably dig up at your local library.
Both of them have circuits that utilize the same parallel arrangement
in one form or another:

Motorola Power Transistor Handbook, 1961 (and probably other years)
(see section on power inverters)

Electronic Circuit Design Handbook, EEE Magazine, 1971-74 (several
different circuits in various sections)

If you can't find those books, can't find any references yourself, and
can't figure out how to set up a simple test circuit to verify its
operation, let me know in a month or so when the weather goes sour and
I'll have more time to spend on your education.

No, don't want to see those. I want to see the exact circuit that you
said you tried and it worked.

www.telstar-electronics.com

On 27 Sep 2006 06:13:29 -0700, "Telstar Electronics"
wrote in
.com:

wrote in
Then show me the circuit that worked.


Frank Gilliland wrote:
Regarding the parallel circuit, I'll save myself the effort of digging
the scanner out of the closet; Here are a couple literary references
from my bookshelf that you can probably dig up at your local library.
Both of them have circuits that utilize the same parallel arrangement
in one form or another:

Motorola Power Transistor Handbook, 1961 (and probably other years)
(see section on power inverters)

Electronic Circuit Design Handbook, EEE Magazine, 1971-74 (several
different circuits in various sections)

If you can't find those books, can't find any references yourself, and
can't figure out how to set up a simple test circuit to verify its
operation, let me know in a month or so when the weather goes sour and
I'll have more time to spend on your education.

No, don't want to see those. I want to see the exact circuit that you
said you tried and it worked.


Vcc
|
|
|R|
|R|
|R|
|
______|_______
| a |
_|_ _|_
\ / D1 \ / D2
_V_ _V_
| |
| |
__|__ __|__
___ ___
_ _


1. Measure voltage at point (a) with respect to ground.

2. Heat D1 with a soldering iron. Watch voltage drop.

3. Let D1 cool. Watch voltage go back up.

4. Heat D2 with a soldering iron. Watch voltage drop.

5. Let D2 cool. Watch voltage go back up.


Thus endeth electronics lesson for today.

Frank Gilliland wrote:
Vcc
|
|
|R|
|R|
|R|
|
______|_______
| a |
_|_ _|_
\ / D1 \ / D2
_V_ _V_
| |
| |
__|__ __|__
___ ___
_ _


1. Measure voltage at point (a) with respect to ground.

2. Heat D1 with a soldering iron. Watch voltage drop.

3. Let D1 cool. Watch voltage go back up.

4. Heat D2 with a soldering iron. Watch voltage drop.

5. Let D2 cool. Watch voltage go back up.


Thus endeth electronics lesson for today.

Ok, that's just what I thought you'd draw. I claim this is useless and
won't work right. If you hook point "A" up to the base an RF device...
it'll do exactly what I described before. Either the base-emitter diode
will be on... or the other diode will be on. If the plain diode is
on... you have no current in the base of the transistor. It will be cut
off... and you have no bias at all. If the base-emitter diode is on...
you'll have some bias... but the tracking diode is off and can't do
anything. How in the world will that track anything, in either case.
Answer: It won't.

www.telstar-electronics.com

On 27 Sep 2006 15:52:43 -0700, "Telstar Electronics"
wrote in
. com:

Frank Gilliland wrote:
Vcc
|
|
|R|
|R|
|R|
|
______|_______
| a |
_|_ _|_
\ / D1 \ / D2
_V_ _V_
| |
| |
__|__ __|__
___ ___
_ _


1. Measure voltage at point (a) with respect to ground.

2. Heat D1 with a soldering iron. Watch voltage drop.

3. Let D1 cool. Watch voltage go back up.

4. Heat D2 with a soldering iron. Watch voltage drop.

5. Let D2 cool. Watch voltage go back up.


Thus endeth electronics lesson for today.

Ok, that's just what I thought you'd draw. I claim this is useless and
won't work right. If you hook point "A" up to the base an RF device...
it'll do exactly what I described before. Either the base-emitter diode
will be on... or the other diode will be on. If the plain diode is
on... you have no current in the base of the transistor. It will be cut
off... and you have no bias at all. If the base-emitter diode is on...
you'll have some bias... but the tracking diode is off and can't do
anything. How in the world will that track anything, in either case.
Answer: It won't.


Well, you just proved your foolishness by:

(1) contradicting the engineers at Motorola and other transistor
manufacturers who use diode biasing in the test circuits for nearly
every bipolar RF power transistor ever made;

(2) proving that you have never actually measured the open-base
voltage of a bipolar RF power transistor (hint: it's less than logic
would dictate);

(3) failing to understand that a bipolar transistor is a CURRENT
amplifier, not a VOLTAGE amplifier;

(4) demonstrating that your internet education didn't include the
basics of semiconductors -- specifically that the Vf/If curve has a
slope greater than zero;

(5) ignoring the fact that those "parallel" diodes which you thought
were "puzzling" were actually in series and used as temperature
sensors for a seperate bias regulator circuit; and

(6) posting your technical ignorance and inexperience in a public
forum where it can be read by any potential buyer of your amp.

So what's next from you, Brain? Some vague, Skippy-esque excuse about
how it's "part of a bigger picture"? Will you pull an Eitner and deny
the facts based on a claim of omniscience? Or will you just go back to
your same old fallacious argument that anyone who has never built a
cheap CB amp doesn't know squat?

The circuit works. If it didn't work for you then either you screwed
it up or didn't understand its function. I'm guessing both.