How Can I Shield My Circuit from EMI Caused by a High-Voltage Pulse Transformer?

In summary, the conversation discusses the issue of EMI caused by a pulse transformer and how to prevent it. The speaker has tried various methods such as using copper mesh and a metal box, but with limited success. They are seeking advice on how to effectively shield their micro-controller and whether grounding the shield to an electrical outlet would be sufficient. The conversation also mentions the importance of determining the frequencies that the equipment is sensitive to and protecting against those.
  • #1
kenw232
9
0
I hit a 1:40 ratio pulse transformer with a 1000V (100mA) sawtooth pulse and it creates a spark gap. Unfortunately it also creates a lot of EMI and my micro-controller and power supply has problems because of it. How do I stop this? How do I know what the wavelength is of the EMI field so I can figure out what size copper-mesh to get? I don't have a spectrum analyzer. I pulse the coil from anywhere from 10Hz to 400Hz if it matters.

Will any mesh diameter work?
http://www.twpinc.com/wire-mesh-material/copper

How about a metal box? Would that be more effective?
http://hollandshielding.com/324-EMI_enclosures

Should I not bother trying to shield the transformer, and instead only shield my micro-controller? I must tie the shield to Earth ground, and the easiest way to do that is just my ground plug in my electrical outlet correct? I tried creating a silver box with 100oz pure silver bars, it did nothing. I though that would at least reduce it somewhat.

Thanks for any help.
 
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  • #2
The EMI from the pulse will not have a single wavelength: it's a pulse.
You should discover (i.e. from the manufacturer) what frequencies your equipment is sensitive to and protect against those.
Of course, you could just try putting the equipment in a solid metal box and/or putting a grounded metal wall (or a full water tank) between the equipment and the pulse source.
 

Related to How Can I Shield My Circuit from EMI Caused by a High-Voltage Pulse Transformer?

1. What is a Faraday cage?

A Faraday cage is a structure or container that is designed to block electromagnetic fields. It is made of conductive material, such as metal, and works by redistributing the electric charge on its surface to cancel out the electric field inside the cage.

2. How does a Faraday cage work?

A Faraday cage works by creating a continuous conductive path around the outside of the cage. This path causes any external electric fields to be distributed around the cage, leaving the inside of the cage electrically neutral.

3. Why would I need a Faraday cage?

Faraday cages are commonly used to protect electronic devices and equipment from electromagnetic interference. They can also be used to prevent electronic signals from being intercepted or to shield sensitive equipment from external electric fields.

4. Can a Faraday cage protect against all types of electromagnetic radiation?

No, a Faraday cage can only protect against electromagnetic radiation within a certain frequency range. It is important to choose the right material and design for the intended use of the cage.

5. How do I know if a Faraday cage is working?

You can test the effectiveness of a Faraday cage by using an electromagnetic field meter. Place the meter inside the cage and see if the readings are significantly lower compared to outside the cage. You can also test by placing a cell phone inside the cage and checking for signal reception.

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