Search found 10 matches
- Fri Dec 10, 2010 5:46 pm
- Forum: General Discussion
- Topic: HELP, Vendor for Film Capacitors
- Replies: 4
- Views: 2298
Re: HELP, Vendor for Film Capacitors
I am not looking for $19 apiece capacitors, 50V Panasonic ECQ-P's would work just fine. Problem is that Panasonic has discontinued production and I've been unable to find a vendor that has Vishay/Sprague Orange drops in the desired values. The absolute values of the capacitors is less importance tha...
- Sun Dec 05, 2010 5:17 am
- Forum: General Discussion
- Topic: HELP, Vendor for Film Capacitors
- Replies: 4
- Views: 2298
HELP, Vendor for Film Capacitors
:? I'm constructing a Headphone Amp with a cross-feed network and would like to use 1% film/foil or metalized film capacitors. Currently, I'm thinking radial polypropylene's would have the best balance of sonic quality, size and cost. Values are: 3.3nF, 22nF, 100nF and 1uF. Can anyone suggest a vend...
- Sat May 01, 2010 8:06 pm
- Forum: General Discussion
- Topic: :? Suggest Quad Op Amp
- Replies: 4
- Views: 2036
Re: :? Suggest Quad Op Amp
Loop gains are 2 or less. Individual amplifier outputs are 6V or less. Power from 12 single supply. Do not need fast slew or large output current. Low supply current is a higher priority than input bias current. This is the application, R6 will be a 20K trimmer. Would an LM324 or LM224 be a good fit...
- Sat May 01, 2010 11:18 am
- Forum: General Discussion
- Topic: :? Suggest Quad Op Amp
- Replies: 4
- Views: 2036
:? Suggest Quad Op Amp
Need a Quad Op-Amp that is negative rail input capable, is there a better choice than a pair of LM358's?
- Mon Apr 26, 2010 5:48 pm
- Forum: General Discussion
- Topic: Please help with Op Amp circuit
- Replies: 9
- Views: 4013
Re: Please help with Op Amp circuit
Adding a 1K pull-down to the output of the buffer works well on bread-board. The floor voltage is very close to 5V now. Thanks MrAl!
- Thu Apr 22, 2010 6:38 pm
- Forum: General Discussion
- Topic: Please help with Op Amp circuit
- Replies: 9
- Views: 4013
Re: Please help with Op Amp circuit
http://s3.postimage.org/OV7Zi.jpg Yes, original circuit, but with your capacitor added to the feedback loop. What I see is R3 and R4 are summing the current from the 5V reference and the output of the buffer (U1b). Current flows out of the 5V source, through R4 and R3, then into the output of U1b. ...
- Thu Apr 22, 2010 2:02 pm
- Forum: General Discussion
- Topic: Please help with Op Amp circuit
- Replies: 9
- Views: 4013
Re: Please help with Op Amp circuit
Please excuse the delay. I have been climbing the learning curve of LTspiceIV for the past few days. I rebuilt the original circuit on bread-board using a different LM358, just in case the first one was some how damaged, but my results were the same. That is, when the buffer input is below 0.7V the ...
- Mon Apr 12, 2010 3:14 pm
- Forum: General Discussion
- Topic: Please help with Op Amp circuit
- Replies: 9
- Views: 4013
Re: Please help with Op Amp circuit
Why is the Edit button hidden?
- Mon Apr 12, 2010 2:59 pm
- Forum: General Discussion
- Topic: Please help with Op Amp circuit
- Replies: 9
- Views: 4013
Re: Please help with Op Amp circuit
While waiting for a reply, I took a long look at the LM358 data sheet. Then I tested the whole circuit with a variety of input voltages on the low-pass filter. The original circuit misbehaves when the input is less than 0.7V. An LM358 won't sink very much current when it's output in near the negativ...
- Thu Apr 08, 2010 3:11 pm
- Forum: General Discussion
- Topic: Please help with Op Amp circuit
- Replies: 9
- Views: 4013
Please help with Op Amp circuit
Hi everyone :smile: I've been building hobby kits and projects from magazines for a while. This is my first try at building something from scratch. I want to use a 25KHz PWM signal to adjust the speed of a 120mm computer fan with 5V to 12V. The PWM output is an open-drain that can take 5mA at 3.3V. ...