emcelhannon Posted November 26, 2017 Share Posted November 26, 2017 Hi, I'm trying to wire a circuit that will use the high voltage lead from an old crt to power an electromagnet. I'm getting no reaction from my coil...lots of juice, no magnetic field. Is it an AC thing? I thought the hp leads on crts were dc. Just in case I took a high voltage diode from a microwave and fit it in, but it made no difference. What are my options? Many thanks for your replies. Ernie Link to comment Share on other sites More sharing options...
John Cuthber Posted November 26, 2017 Share Posted November 26, 2017 The magnetic field from a coil is governed by the current through it. A CRT supply certainly won't deliver much current. You would probably do better with a torch battery. Link to comment Share on other sites More sharing options...
swansont Posted November 26, 2017 Share Posted November 26, 2017 An AC current will give an oscillating field, and the current will be smaller because of the increased impedance from the inductance. You can increase the field by increasing the number of turns in the coil, as long as you aren't power limited. Link to comment Share on other sites More sharing options...
emcelhannon Posted December 26, 2017 Author Share Posted December 26, 2017 Thanks guys. What about powering a relay? I need the electromagnet to come on the moment the high voltage lead makes its spark. Link to comment Share on other sites More sharing options...
John Cuthber Posted December 27, 2017 Share Posted December 27, 2017 Relays are slow. What are you trying to do? Link to comment Share on other sites More sharing options...
emcelhannon Posted January 9, 2018 Author Share Posted January 9, 2018 I want to keep it swinging with a little juice to the repelling electromagnet below it. I'll have an opposing pole facing down on the pendulum. The current from the high voltage lead isn't enough. I tried a neon sign transformer too. Link to comment Share on other sites More sharing options...
emcelhannon Posted January 14, 2018 Author Share Posted January 14, 2018 On 12/27/2017 at 8:20 AM, John Cuthber said: Relays are slow. What are you trying to do? My true goal is to make my son idolize me as mad scientist in the basement. It's an oddly compelling and enduring motivation. What about a mosfet. I want to power a pendulum with a magnet on the tip. The push will be a base electromagnet that triggers on when the pendulum reaches near equilibrium position. The high voltage lead will be connected to the pendulum. The switch will be the close proximity to ground which will be centered beneath. My goal is to create a nice arc at equilibrium position which will send power to the electromagnet. I thought it would be easy. The hv was suppose to actually power the electromagnet, but it's all volts and no amps, sort of. It's just hv art. Any help you can give me would be greatly appreciated. Many, many thanks, Ernie Link to comment Share on other sites More sharing options...
emcelhannon Posted January 16, 2018 Author Share Posted January 16, 2018 come on , guys Link to comment Share on other sites More sharing options...
Andrius319 Posted April 13, 2018 Share Posted April 13, 2018 How is it going? It is already 3 months late, but will try giving some vague hints. First, you can find plenty of similar works by googling 'electromagnetic pendulum'. If you have signal generator you can amplify it with bridge or if heating might be a problem switching type amplifier. Second, you must make sure you produce correct signal you amplify. It either have match resonant pendulum freaquency or detect pendulum position with sensor. Also, starting might be problematic, since for good initial motion it requeres aligment missmatch. Here is one of the weboage which might turn usefull http://www.instructables.com/id/Magnetic-Pendulum/ Link to comment Share on other sites More sharing options...
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