Search found 2803 matches

by haklesup
Mon Sep 08, 2003 3:42 pm
Forum: General Discussion
Topic: battery cables
Replies: 7
Views: 1256

Re: battery cables

Cleaning the Lead oxide (white stuff)off the terminals is a good idea but cleaning the copper oxide off the surface of the wires will do you no good at all.<p>-- here comes another science class :) -- Consider one strand of wire that is oxidized. A cross section of this wire should reveal clean copp...
by haklesup
Fri Sep 05, 2003 4:46 pm
Forum: General Discussion
Topic: A KiloWatt is a KiloWatt...
Replies: 11
Views: 2576

Re: A KiloWatt is a KiloWatt...

Since energy lost to inefficiency in circuits is usually lost as heat, it follows that any heater will convert all of its power into heat regardless of the heating element. Again, I invoke the law of conservation of energy.<p>Some small differences due to varying power factors from elements that are...
by haklesup
Fri Sep 05, 2003 10:21 am
Forum: General Discussion
Topic: high voltage trigger/ ignitor circuit
Replies: 5
Views: 926

Re: high voltage trigger/ ignitor circuit

A furnace ignitor makes a lot of sence especially when you consider that many come with a thermostat that senses that the flame has started. Consider hijacking an entire gas furnace control system and change the orifice for propane. Even better, look at propane heater control systems for RVs and Cam...
by haklesup
Thu Sep 04, 2003 11:17 am
Forum: General Discussion
Topic: high voltage trigger/ ignitor circuit
Replies: 5
Views: 926

Re: high voltage trigger/ ignitor circuit

How big of a spark and do you want to sustain it.<p>There are many ways to make a small spark but if you want a continuous arc you need a bigger circuit. Heck, just touching the 12V leads together should produce a small short duration spark<p>A diode doubler or tripler can generate very high voltage...
by haklesup
Thu Sep 04, 2003 10:54 am
Forum: General Discussion
Topic: toothbrush charger
Replies: 8
Views: 1210

Re: toothbrush charger

Good call RonH. If I didn't do things backwards once in a while, how would I make all that cool smoke.<p>That actually makes the experiment easier because it is simpler to remove turns from a coil than it is to add them. Maybe you can find a spool of wire that is already approximately the right size...
by haklesup
Wed Sep 03, 2003 12:51 pm
Forum: General Discussion
Topic: toothbrush charger
Replies: 8
Views: 1210

Re: toothbrush charger

That is an inductive coupled charging system. You basically have a primary coil in the base unit and the toothbrush has the secondary coil, the rectifier and charging circuits. When you put the toothbrush in the base unit the two coils are nested and they form a transformer.<p>What you need to do is...
by haklesup
Tue Sep 02, 2003 12:42 pm
Forum: General Discussion
Topic: Need weedwacker electronic ignition circuit!
Replies: 4
Views: 1178

Re: Need weedwacker electronic ignition circuit!

I searched on "2 stroke engine controller" and "two-stroke Ignition" and found this tutorial that might help
http://www.imm.dtu.dk/courses/02224/E2.pdf
by haklesup
Thu Aug 21, 2003 1:45 pm
Forum: General Discussion
Topic: Bipolar Transistor Cookbook
Replies: 1
Views: 1191

Re: Bipolar Transistor Cookbook

Conventional Current goes from pos to neg. We use this convention in the majority of engineering calculations with few exceptions.<p>Electron current goes from neg (the source of the electrons - the electrode) to positive (the anode). You can use it this way but you'll need to invert all your answer...
by haklesup
Thu Aug 21, 2003 1:34 pm
Forum: General Discussion
Topic: Diode Voltage multipliers
Replies: 10
Views: 2825

Re: Diode Voltage multipliers

Simply put, there is no getting around the law of conservation of energy and Ohms law.<p>Pin=Pout P=IV (ok, not preciisly ohms law V=IR but derived from it and the power law P=I^2R) <p>So, I*V in = I*V out regardless of the technology you use in between. <p>The only area you have flexibility is effi...
by haklesup
Wed Aug 13, 2003 12:05 pm
Forum: General Discussion
Topic: Best AM Broadcast band Radio for dx?
Replies: 10
Views: 6894

Re: Best AM Broadcast band Radio for dx?

If your shopping for a new radio and the specs are available, you could look at the AM tuner sensitivity spec but the antenna advice is really the best.<p>A quick search on google using "replacing AM antenna" yeilded some articles on modifying the ferrite rod antenna to have a homemade loop antenna ...
by haklesup
Tue Aug 12, 2003 8:17 pm
Forum: General Discussion
Topic: Electrolytic Caps desoldering motherboard
Replies: 5
Views: 2859

Re: Electrolytic Caps desoldering motherboard

Just a little background info:<p>Those caps (and almost all caps on a motherboard) are used primarily for filtering transient noise out of the power supply voltage. These transients are primarily caused by rapid shifts in the demand for supply current as the CPU changes from task to task although so...
by haklesup
Tue Aug 12, 2003 1:38 pm
Forum: General Discussion
Topic: Electrolytic Caps desoldering motherboard
Replies: 5
Views: 2859

Re: Electrolytic Caps desoldering motherboard

There is no trick to desoldering a multi layer board, you just need to be careful not to damage the trace or pad when working on it.<p>Don't heat the connection too long or too hot. This will weaken the substrate. The hot tip of a soldering iron should never be used as a chisel to bend the leads up....
by haklesup
Mon Aug 11, 2003 12:50 pm
Forum: General Discussion
Topic: surface mount LED
Replies: 4
Views: 1013

Re: surface mount LED

I've soldered many fine pitch SMT devices by hand, several things come to mind.<p>I find bulk soldering of many pins at a time using flux/solder paste to be a messy disaster if you do not have the proper IR or forced air reflow systems available. Pin by pin hand soldering is more reliable on any par...
by haklesup
Mon Aug 11, 2003 12:13 pm
Forum: General Discussion
Topic: JFET differences: GP vs. SW vs. VHF vs. UHF
Replies: 5
Views: 1124

Re: JFET differences: GP vs. SW vs. VHF vs. UHF

In that case, don't even mess around with discrete transistors. Since you are basically trying to make a 3pdt switch solid state you should use a switch like the DG411/DG412 or the MAX313/314 (quad SPST) or the MAX4661 (lower on resistance). <p>Similarly numbered Maxim (www.maximic.com) chips have o...
by haklesup
Sat Aug 09, 2003 10:02 pm
Forum: General Discussion
Topic: JFET differences: GP vs. SW vs. VHF vs. UHF
Replies: 5
Views: 1124

Re: JFET differences: GP vs. SW vs. VHF vs. UHF

UHF and VHF transistors are designed to operate at higher frequencies with respect to a number of specific specifications. See a data sheet for all those graphs that have frequency on the X axis. Specific methods of construction and design influence the suitability of a device to be in this category...