Search found 376 matches
- Sun Feb 17, 2002 7:46 pm
- Forum: General Discussion
- Topic: H-bridges and other modules
- Replies: 1
- Views: 2015
H-bridges and other modules
I've tossed the idea into another forum with limited exposure. I'd like some feedback from the people here on this obsession of mine. I've a few (very few) drawings for modules (breadboard compatible) and smt platforms (have you seen the price on these!?) for hobbyists such as ourselves.<p>One that ...
- Wed Feb 13, 2002 6:17 pm
- Forum: General Discussion
- Topic: Old Geiger counter information needed
- Replies: 2
- Views: 2806
Re: Old Geiger counter information needed
I've got an IM-62/PDR-10A by Nuclear Instrument and Chemical Corp.. I have no idea what kind of batteries it takes, and the calibration sticker is too dirty to read. It appeared to be in good shape, and was going for a buck a pound, so I bought it hoping for the best. Can anyone here tell me what ba...
- Wed Feb 13, 2002 6:06 pm
- Forum: Robotics
- Topic: Computing brain size and complexity
- Replies: 15
- Views: 12520
Re: Computing brain size and complexity
I'm sorry that I can't provide the resource to find it but I read of a kind of sea snail that has very few neurons. The number twenty something comes to mind but I can't be sure. The reason it was mentioned in the article was that they are almost large enough to see without magnification. Their larg...
- Fri Feb 08, 2002 5:59 pm
- Forum: General Discussion
- Topic: triac problems..
- Replies: 19
- Views: 15780
Re: triac problems..
I wouldn't be so quick to suspect the inductance of blowing the fuses. Light bulbs have a much lower resistance when cold than when hot. Low voltage lighting may have marginal wiring which will incrrease the warming-up interval. Multiple low voltage bulbs in parallel may be drawing too much of a sur...
- Fri Feb 08, 2002 7:31 am
- Forum: General Discussion
- Topic: Class D amplifier
- Replies: 7
- Views: 4159
Re: Class D amplifier
Some amplifiers have a multistage scheme with a class D supplying the power to a class AB with just a few volts to spare. The class AB stage cleans the signal. Result? A compromise between class AB quality and class D efficiency.<p>Low THD? Unless stated otherwise, THD is rated at 1kHz. The proof is...
- Wed Feb 06, 2002 10:18 pm
- Forum: General Discussion
- Topic: Video Amplification and/or baluns
- Replies: 6
- Views: 3873
Re: Video Amplification and/or baluns
Oops, sorry 'bout that. I looked some terms and found that at 4.5MHz in the gain-bandwidth product, the device stops amplifying. Boy do I feel like a dork! This is partially due to parts that deliberately defeat the amplifier at high frequencies to prevent oscillation. There are opamps made without ...
- Wed Feb 06, 2002 6:22 pm
- Forum: General Discussion
- Topic: Video Amplification and/or baluns
- Replies: 6
- Views: 3873
Re: Video Amplification and/or baluns
The MC33070 series (33071, 33072, 33074) have a gain bandwidth product of 4.5 MHz and a slew rate of 13V/uS. If the phase margin doesn't kill your signal, you may get a volt or two.<p>My limited understanding of baluns leads me to believe that they can only be used with narrow bandwidths.
- Wed Feb 06, 2002 5:58 pm
- Forum: General Discussion
- Topic: LM386 Op Amp
- Replies: 2
- Views: 2437
Re: LM386 Op Amp
I've got the specs right here. I'll send them to you. Now, if anybody else wants to know, they work down to 4V or so. The output is self centering, and the inputs are limited to +/- 0.4V with respect to the negative supply rail. They'd make lousy opamps with their inputs and outputs being incompatib...
- Wed Feb 06, 2002 5:40 pm
- Forum: General Discussion
- Topic: Class D amplifier
- Replies: 7
- Views: 4159
Re: Class D amplifier
I'm no authority, but I'd put the switching frequency at least one decade higher than the highest frequency I wanted to amplify. The output would then go through a passive low pass filter to reduce the switching artifacts. By having the switching rate that high, you also reduce the aliasing.
- Fri Jan 25, 2002 10:41 am
- Forum: General Discussion
- Topic: Need info on PIC16C73A
- Replies: 3
- Views: 2875
Re: Need info on PIC16C73A
I'd actually thought about x-radiating them, but came upon two problems. I don't have a handy source. I don't know if the OTPs have the same EPROM as the reusable ones, just without the window. From a design standpoint it would make sense if EPROM is cheap but windowed ceramic packages are spendy, b...
- Thu Jan 24, 2002 11:26 am
- Forum: General Discussion
- Topic: Need info on PIC16C73A
- Replies: 3
- Views: 2875
Need info on PIC16C73A
I obtained a bunch of OTPs that are likely already burned. I was wondering if these can accept instructions from an external memory. Any help is greatly appreciated. Thanks. <p>If you want to know my excuse for having them, I was picking up stuff at the local scrapyard for a buck a pound. I got some...
- Wed Jan 23, 2002 10:59 am
- Forum: General Discussion
- Topic: Low Vsat transistors ?
- Replies: 13
- Views: 9376
Re: Low Vsat transistors ?
I once had a stereo that ran on a single AA until it was dead as a doornail. The cell wouldn't even power a clock for more than a few weeks. After a cell is discharged to less than 0.9V with a light load, there's not much left to it. So with a two cell torch, any performance below 1.8V is a bonus. I...
- Tue Jan 22, 2002 4:38 pm
- Forum: General Discussion
- Topic: Low Vsat transistors ?
- Replies: 13
- Views: 9376
Re: Low Vsat transistors ?
Saturation voltage varies with collector current, base current, temperature, and coffee brand. I could interpret The Semiconductor Data Book (1968, Motorola) on 2N4001s. Several curves are shown, one crosses 0.2V at 100mA Ic and about 2 mA Ib. At 10mA Ic, the curve crosses 0.2V at about 150uA. If yo...
- Thu Jan 17, 2002 9:09 pm
- Forum: General Discussion
- Topic: smd resistors
- Replies: 3
- Views: 3025
Re: smd resistors
I would guess the last digit to be the multiplier. So 1913 would be 191k. If the fourth digit means something else then the resistonce would read as 190 ohms, not a standard value for three digit resistors. If you measure it with a DMM, that will tell you. Note that this may be a 1% or better resist...
- Thu Jan 17, 2002 10:05 am
- Forum: General Discussion
- Topic: Cell phone boosters
- Replies: 9
- Views: 5422
Re: Cell phone boosters
You've got my curiosity up. What sticker things? What company makes them? I only get two channels, KVOS and KVCR. Without seeing one I can only guess that at five bucks apiece they're a reflector to keep power from going where you know there's nothing there to recieve it.