## Search found 341 matches

Mon Feb 28, 2005 9:56 am
Forum: General Discussion
Topic: Channel Phase Shift Measurements and Phase Equalizing Fi
Replies: 4
Views: 1131

### Re: Channel Phase Shift Measurements and Phase Equalizing Fi

To do the analysis, you need a vector network analyzer (VNA). This applies a swept frequency to the input and plots amplitude and phase on the output. Phase equalization using allpass networks, in my experience anyway, is part science and part art. It would help if you could simulate the equalizer, ...
Thu Feb 24, 2005 11:23 am
Forum: General Discussion
Topic: Yes , or No ?
Replies: 9
Views: 1989

### Re: Yes , or No ?

I'm baffaloed by your question. How can two waveforms, 90 degrees out of phase, have a constant absolute value difference of 2 volts when they cross each other (diff=0) twice per cycle? Am I missing something?
Thu Feb 17, 2005 1:42 pm
Forum: General Discussion
Topic: Prevention of Fine Soot Entering Room
Replies: 15
Views: 3384

### Re: Prevention of Fine Soot Entering Room

Are you sure there is no leakage in the heat exchanger? I once had an open wood-burning fireplace that I added a forced-air tubular grating to. After a short time, the fire burned out some of the screws holding the tubing to the grate. The fan apparently sucked combustion products from the flame, wh...
Wed Feb 16, 2005 11:45 am
Forum: General Discussion
Topic: impedance comverter
Replies: 11
Views: 2402

### Re: impedance comverter

My guess is he's looking for a negative impedance converter.
Tue Feb 08, 2005 3:01 pm
Forum: General Discussion
Topic: 78L05
Replies: 8
Views: 1982

### Re: 78L05

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>why is the period for 60Hz 7.5 ms in the handbook and 8.33ms in your example? <hr></blockquote> Well, the period IS 8.33ms, but, due to droop, the rectifier will start to conduct before the peak of the next half cycle....
Tue Feb 08, 2005 2:44 pm
Forum: General Discussion
Topic: 78L05
Replies: 8
Views: 1982

### Re: 78L05

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by philba: larger. Here's how I would do it.<p>Your 12V DC wall wart probably puts out around 17VDC peak (1.414 * 12). You want solid DC input of around 8V to the 78L05. So lets say around 9V of rippl...
Tue Feb 08, 2005 2:32 pm
Forum: General Discussion
Topic: Relay Driver Protection Diode
Replies: 12
Views: 2859

### Re: Relay Driver Protection Diode

1N4148/1N914 is more than adequate for a 5V (or 12V), 40ma relay snubber. As Will says, the peak current will never exceed the steady-state relay current, since that current, which was flowing through the (transistor) switch, is simply diverted through the diode until the current decays. Take a look...
Tue Feb 08, 2005 1:58 pm
Forum: General Discussion
Topic: Battery check
Replies: 11
Views: 2558

### Re: Battery check

Do you want the entire circuit, including the LED, to be powered by the two AA batteries, or do you have a separate power source?
Tue Feb 08, 2005 1:39 pm
Forum: General Discussion
Replies: 8
Views: 2052

Do a Google search for "cockroft-walton".<p>[ February 08, 2005: Message edited by: RonH ]</p>
Thu Jan 06, 2005 10:40 am
Forum: General Discussion
Topic: Voltage follower with variable offset?
Replies: 13
Views: 3104

### Re: Voltage follower with variable offset?

You can also do it by classic op amp gain equations: <blockquote><font size="1" face="Verdana, Helvetica, sans-serif">code:</font><hr><pre> attenuator non-inv. gain inv. gain || || || Vout=Vin*R2/(R1*R2)*(R3+R4)/R3 - Vref*R4/R3 </pre><hr></blockquote><p>Where R1 and R2 are the input voltage divider,...
Wed Jan 05, 2005 7:59 pm
Forum: General Discussion
Topic: guitar overdrive
Replies: 8
Views: 2137

### Re: guitar overdrive

The transistors with caps in series with the bases won't work. Even if you get rid of the caps, it won't work. You need some resistors in that circuit. I don't know enough about the distortion you want, to make recommendations. Your gain control circuit also needs a resistor from U1A inverting input...
Wed Jan 05, 2005 7:46 pm
Forum: General Discussion
Topic: Voltage follower with variable offset?
Replies: 13
Views: 3104

### Re: Voltage follower with variable offset?

Your function is Vout=Vin-5. You can do this with an op amp, a 5 volt reference (the A/D's reference?), and two pairs of equal-valued, well-matched resistors. One pair forms a voltage divider of your temperature signal, with the center tap connecting to the non-inverting input. The other matched pai...
Wed Jan 05, 2005 11:16 am
Forum: General Discussion
Topic: diode work at Hi-freq.
Replies: 5
Views: 1489

### Re: diode work at Hi-freq.

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by david753: indeed, there is a pair of diodes embeded in AD9057 in front of analog input. But, in the real situation, the output is not correct when the input signal is over voltage (about 2-3Vpp). <...
Wed Jan 05, 2005 6:58 am
Forum: General Discussion
Topic: diode work at Hi-freq.
Replies: 5
Views: 1489

### Re: diode work at Hi-freq.

I doubt that the input diodes are designed to handle more than a few milliamps. See p.32 of this document from Analog Devices<p>[ January 05, 2005: Message edited by: RonH ]</p>
Thu Dec 23, 2004 10:36 am
Forum: General Discussion
Topic: Electromagnetic physics question
Replies: 41
Views: 7658

### Re: Electromagnetic physics question

Oops! Sorry for the double post.<p>[ December 23, 2004: Message edited by: RonH ]</p>