Radio oscillator/receiver?

reply to post by swan001


Sorry, was away for a couple of days, but yes, that is what I am talking about, you will just have to change the configuration of your contact. The moment the coil is energised, and the magnetic material is attracted to the coil, the circuit will be broken.. The more turns you have on that coil the higher the inductance will be and the higher the back-emf when you break the gap, so the larger the spark you will get. You can wire your whole coil around an iron core, or a ferrite that you get out of an old MW-receiver, to get a higher inductance.

reply to post by Hellhound604


Okay, sincere thanks, mate.

I'll give it a try. Thanks again!!

reply to post by Hellhound604



So this above pic is a pic of my coil. I spent last couple of days winding it up (I don't have a winding machine, I had to do it manually) using light-gauge copper wire from an old guitar pickup. I threw in all of the copper which was in the pickup. Just in case you ask, No, the fragile copper thread never broke, it's all one long wire; and Yes, it's all wounded in the same direction. The core is a pole from the pickup - which I know for a fact that it transfers magnetism like a dream. The three pins are just there to hold the copper coil in place. Coulda have waxed it but I was reluctant to put heat onto the fragile copper thread. The paperclip beside is just so you can get an idea about the coil's size.

So, the reason why I posted the pic is simply because I wanted to know if you reckon the coil had enough turns on it.

I intend to plug the contact point wire to hot, the other side to ground, and plug the movable piece of metal (which the coil should attract once magnitized) to ground. The whole thing should short-wire to ground when the metal piece (not shown in the pic, 'cause I didn't make it yet) touches the contact.

BTW, 40 years you do this... I realize now it means back in the 70's... You're lucky to have seen these years. The Cold War, the new age movement, the birth of modern rock, the crooners... I envy you; as for me I'll never know how was the world before the 90's.

Yours,

Swan

reply to post by swan001


that is a very small coil .... I was thinking about a much larger coil, with a couple of hundred turns on it. When I played around with those things, I couldn't make the things as small as yours. I was only about 11, and had a very limited budget and resources. My stuff was a couple of hundred turns around a 6-inch nail. Pretty soon after that I moved on to valves, and then later transistors.

reply to post by Hellhound604


What gauge were you using? I only have the thinnest, which is present in my guitar pickups. I'll have to check how much turns there are in my coil, but I am positive it's over 300. Over by far... I tried keeping a tension on it so that it wasn't too fluffy.

EDIT: I quickly checked how many turns a guitar coil has and it has over 1000 turns. That means I have that many turns in my coil... and my coil is smaller than a guitar pickup, which means it has even more turns than the pickup had.

reply to post by swan001


I stripped it from an old transformer, so I guess it was about AWG 30, or thereabouts. Have you tried energizing your unit yet? If it doesn't energise, you might consider up the current by increasing the voltage, but I have no idea what size wire you are using, so I can't even guess what max. current will be safe before you start burning your wires. Once you have the basic vibrator running, you can consider adding a secondary winding over that, there is a linear relationship between the amount of turns on the primary vs. the amount of turns on the secondary, so if you have 100 turns on the primary and 1000 on the secondary, the voltage across the secondary will be 10x more that what you put in (and that includes the voltage spike as you break/make the circuit).

If you really want to have fun, and can determine the resonance frequency of your primary circuit, you can do the sums to match the resonance frequency of the secondary, and then you'll have a mini-Tesla coil.

reply to post by Hellhound604


my wire gauge would be forty-ish, according to my quick searches.

I didn't energized it yet, I'll try it tonight or tomorrow night, when I get time off from my job. I still have to solder the delicate leads into more permanent connectable wires.

I'll get back to you once that's done.

See ya,

John.