Forums

Amplifer Design

Started by Cursitor Doom October 13, 2019
Cursitor Doom wrote...
> > Winfield Hill wrote: >> Cursitor Doom wrote... >>> >>> ... drop a couple of closely-matched jellybeans in there in >>> place of Q8 and Q13 and in this x-amp at any rate, given its >>> modest task, will quickly be back in business again. >> >> The two BJTs are npn and pnp types and cannot easily be closely >> matched, nor do they need to be.** Plop some parts in there >> and let us know what happens. >> >> ** Recenter the screen with the HORIZ POSN control. > > Indeed so. I'm guessing the hardest part is going to > be finding PNPs in my junk box that are fast enough.
Any old PNP will be fine, tit doesn't have to be fast, the collector is going into a summing junction. Even a 2N3904 / 2N3906 will work fine. -- Thanks, - Win
Jan Panteltje wrote...
> > I bought a 2400 W water boiler, for coffee that is. > Plugging it in did indeed boil 1.5 liter water in > about 3 minutes, but it also caused a dip ...
2400 watts, that's ridiculous. The most they sell here is 1500 watts, that's more than fast enough. Trade it in for a smaller one. -- Thanks, - Win
On 16/10/2019 16:24, Winfield Hill wrote:
> Jan Panteltje wrote... >> >> I bought a 2400 W water boiler, for coffee that is. >> Plugging it in did indeed boil 1.5 liter water in >> about 3 minutes, but it also caused a dip ... > > 2400 watts, that's ridiculous. The most they sell > here is 1500 watts, that's more than fast enough. > Trade it in for a smaller one.
Most UK kettles are 3kW although there is a trend towards 2.4kW for new portable appliances as the full 13A load stresses the fused plugs somewhat. Much more of a problem with electric fan heaters than kettles which typically only present a load for a couple of minutes at most. -- Regards, Martin Brown
On a sunny day (16 Oct 2019 08:24:14 -0700) it happened Winfield Hill
<winfieldhill@yahoo.com> wrote in <qo7cmu0q6g@drn.newsguy.com>:

>Jan Panteltje wrote... >> >> I bought a 2400 W water boiler, for coffee that is. >> Plugging it in did indeed boil 1.5 liter water in >> about 3 minutes, but it also caused a dip ... > > 2400 watts, that's ridiculous. The most they sell > here is 1500 watts, that's more than fast enough. > Trade it in for a smaller one.
No, I already like it very much: https://www.artencraft.nl/nl/siemens-tw86103p-waterkoker-15l-zwart-268677.html?gclid=EAIaIQobChMIzKqirJmh5QIVRuJ3Ch1hnwA2EAQYASABEgLmFfD_BwE Electronic control:-) It is more efficient than boiling water in the microwave (what I did till now) That way it will pay itself back in a few years. And it is made in the EU by an EU based (German) company. As the US pRecedent likes damaging world trade I answer by not buying US stuff. 1500 W PUSSIES!!! ;-) Found some good Linux laptops locally for sale..
On Wednesday, 16 October 2019 16:24:34 UTC+1, Winfield Hill  wrote:
> Jan Panteltje wrote... > > > > I bought a 2400 W water boiler, for coffee that is. > > Plugging it in did indeed boil 1.5 liter water in > > about 3 minutes, but it also caused a dip ... > > 2400 watts, that's ridiculous. The most they sell > here is 1500 watts, that's more than fast enough. > Trade it in for a smaller one.
Not at all. I just checked the rating label on my "electric kettle". (Almost every household in the UK has one of these.) Mine is rated at 220 - 240V, 2500 - 3000W. Most UK household mains supplies are about 240V single phase and have a main fuse rated at 80 or 100A. Larger houses often have 3-phase 240V (phase to neutral) at 100A per phase. (The "official" voltage is 230V but this is just for harmonisation purposes with the rest of the EU. The specified tolerances allow the real voltage to be around 240V for most areas.) John
On Wed, 16 Oct 2019 07:31:21 GMT, Jan Panteltje
<pNaOnStPeAlMtje@yahoo.com> wrote:

>LOL >not everybody is the same, I am fighting with software. >Real fun, my systems got attacked by one of the most evil ones, the well known Jan Panteltje. >I bought a 2400 W water boiler, for coffee that is. >Plugging it in did indeed boil 1.5 liter water in about 3 minutes, but it also caused a dip in the mains >that in turn caused my main PC reiserfs to see bad sectors, >Rescue failed.
2400 W is only 10 A steady state i.e. 24 ohm resistance. Unfortunately the cold resistance is quite low, until the resistor reaches nominal operating temperature, so the cold start current can be much larger than 10 A.
On Wed, 16 Oct 2019 08:20:00 -0700, Winfield Hill wrote:

> Any old PNP will be fine, tit doesn't have to be fast, > the collector is going into a summing junction. Even a 2N3904 / 2N3906 > will work fine.
Well I'm mightily relieved you said that, Win, because I do happen to have a very large amount of both polarities in stock. THANKS!!! :) -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition.
On Wed, 16 Oct 2019 16:35:58 +0000, Jan Panteltje wrote:

> 1500 W PUSSIES!!! > ;-) > > Found some good Linux laptops locally for sale..
Are you going to Rosmalin for the big electronics swap meet next March, Jan? -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition.
On 15/10/19 7:20 pm, Jan Panteltje wrote:
> I was referring to mixing down 2.4 GHz to 1.5 GHz or so for use with an RTL_SDR USB stick as spectrum analyzer, > that I did.
...
> So, as to GHz: > https://www.ebay.com/itm/272411458376 > much more fun to play with than old boat_anchors. > that is what my xpsa spectrum analyzer software runs on.
The RTL-SDR (listening) community seems to think that this genuine "RTL-SDR v3 Blog" version is very much better than the cheap generic TV dongles that have the same chipset. Ok, I grant that it has a TCXO and the "Q-branch" mod for HF listening, but... What else is it about this specific dongle that makes it better? If you know and have time to answer, of course... Clifford Heath
On Wed, 16 Oct 2019 19:43:09 +0000, Cursitor Doom wrote:

> Well I'm mightily relieved you said that, Win, because I do happen to > have a very large amount of both polarities in stock. THANKS!!! :)
Just wondering if I should try to match pairs by Beta as closely as possible. I have a nagging suspicion I really should make that extra little bit of effort. -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition.