Prev: I?ll write probability of total extermination in the period of future month. According to their plan, the first 2*3.5TeV collisions will be performed the 30-th of March.
Next: The first 2*3.5TeV collisions will be performed the 30-th of March. CERN's plan of Earth explosion.
From: Kari Laine on 17 Mar 2010 04:16
Hammy wrote:
> On Tue, 16 Mar 2010 19:29:12 +0200, Kari Laine <klaine8(a)gmail.com>
> wrote:
>
> Johns giveing you a nice detailed instruction but I see from your sig
> that you are at least familiar with PIC's so you could build your own.
>
> Here is a pretty good one.
>
> http://ironbark.bendigo.latrobe.edu.au/~rice/lc/

Ok thanks. That should be interesting project to make.
And also easier to use. Will save the link and do it later.

Best Regards
Kari
From: Bob Masta on 17 Mar 2010 09:29
On Tue, 16 Mar 2010 22:01:43 +0200, Kari Laine
<klaine8(a)gmail.com> wrote:

>I should have mentioned that I am not totally ignorant about electricity
>and electronics. I know the passive components quite well but transistor
>has always been difficult to me. I had electronics as hobby when I was a
>kid up to something round 16 years old. Then I was in the UNI and
>learned something(I am a dropout). Then worked in computer business.
>Now I am retired and though that why not...
>
>I have had 220V chocks something round 5 times totally in my lifetime
>and they really hurt. Luckily the hart was not stopped. Nowadays I
>triple check before touching anything. But naturally accidents could
>happen. I am mainly interested the low-voltage electronics (at least now).
>
>The amplifier thing I mentioned turned up nicely.
>I got used car audio amplifier for about $90 from auction site in Finland.
>
>Specs:
>
>APA4400G
>100W x 4 Channel Amplifier
>Maximum Power Output 300 W (75 W x 4)
>Continuous Average Power Output 200 W (50 W x 4 into 4 ohms 20Hz-20kHz @
>0.04% THD)
>Maximum Power Output 700 W (175 W x 4)
>Continuous Average Power Output 400 W (100 W x 4 into 4 ohms 20Hz-20kHz
>@ 0.02% THD)
>Typical 2-ohm Stereo 130 W x 4 @ 0.2% THD
>Typical Bridged Power 250 W x 2 @ 0.2% THD
>Dynamic Output Control Bass Extender Control 0-12dB
>Adjustable 4-Channel 50Hz-200Hz, 24dB/oct. High/Low Pass Crossover
>2-Channel Non-Fade Line-Level Output
>Mixed-Mode Operation
>Bridgeable 4-, 3-, or 2-Channel Operation
>Pulse-Width Regulated MOSFET Power Supply
>
>So is this good one or bad?
>
>I have never worked with car amplifiers. But I think it must be single
>supply 12V with lot of amperes (I have a lab power supply which probably
>can cope). And what is good that according the manual there seems to be
>all possible protections for misuse. I only hope the seller is honest...

You hit the nail on the head with your observation
about the 12V power supply. My personal feeling
is that even if this amp is free it will not be
worth the effort and expense of getting it working
on your bench. I'd vote to hold out for a cheap
home stereo amp. Even units from 40 years ago
should be fine for this. I imagine that as people
buy 5- and 7-channel "home theater" systems, their
old 2-channel units will be cheap or free.

Best regards,


Bob Masta

DAQARTA v5.10
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, FREE Signal Generator
Pitch Track, Pitch-to-MIDI
DaqMusic - FREE MUSIC, Forever!
(Some assembly required)
Science (and fun!) with your sound card!
From: John Fields on 17 Mar 2010 11:14
On Wed, 17 Mar 2010 10:15:15 +0200, Kari Laine <klaine8(a)gmail.com>
wrote:

>John Fields wrote:
>> On Tue, 16 Mar 2010 19:29:12 +0200, Kari Laine <klaine8(a)gmail.com>
>> wrote:
>>
>>
>>> Now when I have you attention you hopefully don't mind a question.
>>>
>>> How to find out capacitance and inductance with using function generator
>>> and scope? Is it easy,not so easy, hard, very hard or impossible?
>>> I remember seeing this somewhere in the net, but don't find it now.
>>
>> ---
>> It's pretty easy.
>
>Thank you! Even I understood. If you have time the second method would
>be interesting.

---
Today!

JF
From: Kari Laine on 17 Mar 2010 14:00
Bob Masta wrote:
> On Tue, 16 Mar 2010 22:01:43 +0200, Kari Laine
> <klaine8(a)gmail.com> wrote:
>
>
> You hit the nail on the head with your observation
> about the 12V power supply. My personal feeling
> is that even if this amp is free it will not be
> worth the effort and expense of getting it working
> on your bench. I'd vote to hold out for a cheap
> home stereo amp. Even units from 40 years ago
> should be fine for this. I imagine that as people
> buy 5- and 7-channel "home theater" systems, their
> old 2-channel units will be cheap or free.
>
>
> Bob Masta
>
> DAQARTA v5.10
> Data AcQuisition And Real-Time Analysis
> www.daqarta.com
> Scope, Spectrum, Spectrogram, Sound Level Meter
> Frequency Counter, FREE Signal Generator
> Pitch Track, Pitch-to-MIDI
> DaqMusic - FREE MUSIC, Forever!
> (Some assembly required)
> Science (and fun!) with your sound card!

Ok Bob, Thanks!
Will keep eyes open.

Best Regards
Kari



--
PIC - ARM - DISPLAYS - RELAYS - MODULES - CONVERTERS - I2C - SPI -
KEYPADS - ACCESSORIES
http://www.byvac.com (I am just a satisfied customer)
From: John Fields on 18 Mar 2010 20:14
On Tue, 16 Mar 2010 13:14:36 -0500, John Fields
<jfields(a)austininstruments.com> wrote:



>Another way is to use a resistor of a known value in series with the
>unknown cap or coil:
>
> +-------+
> +-----[10K]----+<----[X10 PROBE]---|VERT |
> | | | |
> | | | |
> [FUNCTION GEN] [DUT] | SCOPE |
> | | | |
> | | | |
> +--------------+<------------------|GND |
> +-------+
>
>I've gotta go do some chores, but I want to get this off instead of
>waiting until later to send the whole thing, so I'll finish it when I'm
>done...

OK.

For the cap, set up your equipment like this:


E1 +-------+
|<---------------------------------|VERTA |
| E2 | |
+-----[10K]----+<----[X10 PROBE]---|VERTB |
| | | |
| | | |
[FUNCTION GEN] [DUT] | SCOPE |
| | | |
| | | |
+--------------+<------------------|GND |
+-------+

Using the sine wave output of your function generator, set its output,
E1, to any convenient level and then tune it to the frequency which
causes E2 to be 1/2 the voltage of E1.

Then solve:

1
C = ----------
2pi f Xc

where C will be the capacitance in farads,
2pi is 6.28,
f is the frequency which causes E2 to be 1/2 of E1, in Hz,and
Xc is 5800 ohms.

Why 5800 ohms?

That's the capacitive reactance you need in order to get E2 equal to
half of E1 at any frequency.

Ergo, with a constant reactance, capacitance will go inversely with
frequency.

JF
First  |  Prev  |  Next  |  Last
Pages: 1 2 3 4 5
Prev: I?ll write probability of total extermination in the period of future month. According to their plan, the first 2*3.5TeV collisions will be performed the 30-th of March.
Next: The first 2*3.5TeV collisions will be performed the 30-th of March. CERN's plan of Earth explosion.