I cleaned out the junk room this weekend and found two old tube tvs, so I cracked them open and salvaged the flyback transformers. (If you do this, make sure to discharge the tube before messing around inside the TV.) It was a rainy weekend so I was stuck inside, so I decided to make a Jacob’s Ladder out of one of the flybacks. I needed a circuit to drive the flyback so I thought I’d try one of the 555 timer circuits I’ve seen online.

For the next step in decreasing the chances of killing myself, I’ll be making an isolation transformer. An isolation transformer is a 1:1 transformer where the output is not referenced to ground. So if an isolation transformer is connected to mains, then the output should be 120 volts. You could theoretically touch the live wire (don’t do that) since it is not referenced to ground, so there would be no “return path”, but if you were to touch both hot and neutral, you would get a shock.

Some of my recent projects have had me tinkering with AC mains voltage more than usual, so I figured it is time to get serious about my bench safety. My plan is to build several pieces of equipment that should decrease my chances of killing myself. First, I will build a fused gfci power source that will trip if I do something stupid. Next, I’ll build an isolation transformer and then a current limiter.

During my previous project, the slayer exciter, I kept blowing transistors trying to pump too much current through them. While I was troubleshooting the circuit, I needed a quick way to test the transistors I was using, so looking around, I found this simple transistor tester circuit using a 555 timer. The 555 drives the transistor in order to blink the led. If the led is full on or off, then the transistor is dead.

I’ve been wanting to experiment with some high voltage projects like a jacob’s ladder, a tesla coil, or a maybe a plasma speaker, but at the moment, I don’t have any good power sources. I’d like to find an old neon sign transformer, but I may just settle for pulling the flyback transformer out of an old tv set. In the mean time, I ran across a small circuit called a slayer exciter that I could build with parts I have on hand.

Over the holidays, I picked up a second hand outernet kit to play around with. The kit consists of an sdr dongle, a low noise amplifier, and an L-band patch antenna and can be purchased new from https://outernet.is. What is outernet? Well, outernet is a filecasting service that beams community submitted and curated content from three Inmarsat satellites. Its sort of like a very slow off-grid news feed. The three satellites are: