Basics

Question about LM334 current source
I would like to use the LM334 with 9V batteries to produce an approximate 3mA constant current through a diode. But I am a little confused by the device schematic. This device has three leads (V+, ADJ, and V-) --- I have put a 25 ohm resistor between ADJ and V- to select the current I want. But I'm not sure where t... 1 Jun 2010 21:55

Sealed lead acid battery maintenance?
I would like to learn something about proper care of sealed lead acid (SLA) batteries. Is there any good authoritative science on how SLA batteries should be cared for? I am searching... I suppose battery makers/distributors would be one of the best sources of information about that? Specifically... I wonder wh... 9 Jun 2010 17:35

Difficulty identifying SMD semis via markings
I've never had to look up a SMD semi before now. Unlike JEDEC codes, these less-than-brief alphanumeric codes have no standard that I can find. And if there's no manufacturer mark (or it has become illegible), there's no hope of finding a replacement. In my case: HFJ (the "J" is smaller than the others), 3... 29 May 2010 09:12

Resistor values with a PUT
From what I have read, the gate of a PUT is what determines its threshold voltage, so you would control that with two resistors, one between positive and the gate, and the other between the gate and ground. I put together a circuit using 1K for both resistors, and got a certain behavior (pulsing an LED). I then tri... 26 May 2010 21:22

resistor value for LM317
usually a fixed resistor value of 220 ohm is used, with a 5k trimmer. Is there any problem if I use a 450 ohm resistor with a 10k trimmer? Maybe the current on the regulation pin will be too low? Any other possible problem? thanks ... 26 May 2010 19:11

Subtractor circuit impervious to components tolerance?
Hi, I'm wondering if there's some circuit configuration (presumably an op-amp based design) that would subtract two signals (say, two audio signals) in a way that is *100% and absolutely unaffected* by components tolerance. I do not mean using 0.1% tolerance resistors, or matched resistor networks, or adding ... 27 May 2010 13:44

Dave cannot stay awake
I don't know how many times I have fallen asleep so far, but am giving up and laying down. Sorry, bit even coffee isn't doing it for me. Haven't gotten a damn thing done, and don't think I am going to at this point. Call if you need anything. dave ... 8 Jun 2010 12:35

Bode ploting
I am a Portuguese science student and although I am a little ashamed to be doing this question, I really need to do it as I have a practical exame this week. One of the tasks we have to do is to make a frequency analysis of a circuit in order to get a bode plot. I know how to do it making manual increments of fr... 24 May 2010 09:02

A question regarding voltage controlled oscillators
Maybe this is a stupid question, but could some electronics guru clarify this a bit ? Current voltage controlled oscillator designs, based on fixed frequency oscillators - e.g., Colpitts have a resonator and the feedback amplifier. The resonator typically consists of a LC tank circuit, with varactors and fixed val... 24 May 2010 02:36

Why are my LEDs still glowing...?
Ade wrote: don(a)manx.misty.com did gone and wrote: In article <MPG.26634d95671d95009896f8(a)news.enta.net>, Ade wrote: [diode in series] That, as it happens, fixed the problem completely (no more afterglow). By using green LEDs on "High" and "Medium", I only needed to add 1 diode, in... 23 May 2010 23:23