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Hi
I'm working on my first energizer build. Trying to do it all by the book. However some things have come up that I don't quite understand.
I've been using an oscilloscope to see what's happening on the fet that the trigger coil is hooked to, specifically the base and collector pins, and the circuit that I'm testing is exactly the one in the beginners book, page 65 (screenshot at the end)
This first show shows my question at a fairly slow rate - 10ms/div.
The Blue trace is the base (the trigger coil), and the yellow trace is the collector - one of the driver coils.
You can see pretty clearly that when the trigger voltage rises high enough, the FET turns on, there are a bunch of spikes, and then it turns off. The spikes seem to me to be an oscillation caused by the driver circuit overpowering the trigger, causing the trigger circuit to inverse follow the driver circuit, which rapidly turns the FET on and off until the trigger output finally goes below the FET threshhold and we have peace until the next magnet comes over the coil.
This second shot is just an time amplification of the first - here we're at 500 microseconds/div. I think this confirms my story above, that when the trigger turns the FET on, the current (voltage?) induced in the trigger by the driver wire inversely follows the driver wire, and as the magnetism builds in the coil, the trigger drops low enough to turn the FET off, causing the driver spike, which first pulls the trigger way down, and then, since the driver is off momentarily, the trigger signal rises back to it's magnetized level, which starts the process all over.
My observation is that these traces don't agree with the information in the SG Advanced book P 51 & 55.
Further, I was at first surprised by the oscillation of the trigger pulse, until I realized that the driver wire current is inducing this signal in the trigger wire.
I've not seen any scope traces in the posts that I've looked at, so I'm just wanting to know if what I'm seeing is correct behavior for these 2 pins of the #1 FET
This is the circuit that I'm testing:
I'm working on my first energizer build. Trying to do it all by the book. However some things have come up that I don't quite understand.
I've been using an oscilloscope to see what's happening on the fet that the trigger coil is hooked to, specifically the base and collector pins, and the circuit that I'm testing is exactly the one in the beginners book, page 65 (screenshot at the end)
This first show shows my question at a fairly slow rate - 10ms/div.
The Blue trace is the base (the trigger coil), and the yellow trace is the collector - one of the driver coils.
You can see pretty clearly that when the trigger voltage rises high enough, the FET turns on, there are a bunch of spikes, and then it turns off. The spikes seem to me to be an oscillation caused by the driver circuit overpowering the trigger, causing the trigger circuit to inverse follow the driver circuit, which rapidly turns the FET on and off until the trigger output finally goes below the FET threshhold and we have peace until the next magnet comes over the coil.
This second shot is just an time amplification of the first - here we're at 500 microseconds/div. I think this confirms my story above, that when the trigger turns the FET on, the current (voltage?) induced in the trigger by the driver wire inversely follows the driver wire, and as the magnetism builds in the coil, the trigger drops low enough to turn the FET off, causing the driver spike, which first pulls the trigger way down, and then, since the driver is off momentarily, the trigger signal rises back to it's magnetized level, which starts the process all over.
My observation is that these traces don't agree with the information in the SG Advanced book P 51 & 55.
Further, I was at first surprised by the oscillation of the trigger pulse, until I realized that the driver wire current is inducing this signal in the trigger wire.
I've not seen any scope traces in the posts that I've looked at, so I'm just wanting to know if what I'm seeing is correct behavior for these 2 pins of the #1 FET
This is the circuit that I'm testing:
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