Electrical Faux Pas

[angryScientist]

Here is a helpful guide. It discuses which capacitor, resistor to use at which frequencies,
board layout for RF, soldering, PC board etching. It's just some useful tips for RF design.

http://home.sandiego.edu/~ekim/otherjunk/rf_proto.pdf


I found it through this site:
http://www.101science.com/rfdesign.htm

It also has links to dozens of Transistor Tutorials.
http://101science.com/tranbasic.htm

[wattsup]

@z_p_e, @ERS and all

Thanks for your infos.

OK the transistor is understood (cooked only one more), thanks again.

Now I know I can pulse the base with a resistor and capacitor. Is there an easy way I can calculate the resistors and caps I would need to let's say take 10 transistors and pulse each base at it's own time?

Also, instead of resistors, I think if I used 10 pots and instead of using a capacitor, what if I used a variable capacitor (VC), what type of values should I look for?

Would a pot and a VC together enable me to adjust these base on times, on the fly.

That would be a coup for me.

[z_p_e]

wattsup,

If you are referring to EM's circuit, the voltage through the resistor/capacitor on the base is more of a "ramp" than a pulse.

Maybe you should explain what you want to do with these 10 transistors. Do they all switch ON at the same time, or will each have their own timing input?

In regards to variable resistors (pots) and caps, sure you can use these to vary the timing on the fly. Keep in mind however that you will likely not find a variable cap value much higher than a few hundred picofarads or so, definitely not in the uF's. Normally, you would not need to vary both anyway, just use a pot. If you really need to vary the cap in addition to the resistor, then use a rotary switch and switch in various ranges of cap values. That's how it is normally done.

[wattsup]

@z_p_e

The 10 transistors would be pulsed at different times or in succession, either on or off. I am saying 10 but it could be 4 or 5 transistors. I have coils and devices here that have been crying for pulsing and I am up to that point.

OK, so what you say about the pots and VC's is that their range of action is very tight, meaning I would need to have a good idea about the actual final values and gets pots that are close to that range to then fine tune it. That's a bummer, because the ranges are so wide to start with.

For the resistors, is it possible to use a decade box and add a pot in series. Then I could just switch resistors on the box and use the pot to fine tune at each resistance, or do I need a different pot for each resistance in the decade box.

For the capacitors, what if I found an old radio tuner. Does this have more range. Or can I find a switchable small capacitor bank and put a VC in series, like for the resistors, to better fine tune at each fixed cap value.

[wattsup]

@all

Since z_p_e is no longer around, thought I'd put this here.

One thing that has bugged me for a long time now was how to skin magnet wire. When you have 20 of these to do using sand paper, it starts getting messy, your fingers ache and it takes forever.

So, I just found this video attached below.

If anyone has a better idea, I'm all ears, uh eyes, uh fingers, uh whatever. lol