To any who viewed my royer oscillator thread - this thread is a continuation of sorts.
My plan for making the circuit as safe as possible was to clamp the input voltage such that the output could never rise above the required 500 VRMS.
I did some circuit characterization and found that at around 4.5-4.75V with a loaded or un-loaded output the royer oscialltor measured around 525-550 VRMS on a DMM.
Lucky me, a 4.7V zener is a common component - so i went about designing a simple input stage of components.
I came up with a circuit, and went straight to breadboarding it prior to simulation...breadboarding did not work - the clamp worked independent of the royer, and the royer worked independently of the clamp..but once i put them together neither part worked - and a lot of good components gave their life as i tried again and again. In the schematics i will post refer to the C1/R2 node, this point never went above 0.6VDC...i had no idea what was going on.
So i went back to simulation to try and see what was going on...the story begins here.
(note:
green trace = V1/R1 node
blue trace = D1/R1 node
red trace = C1/R2 node)
Schematic 1 was a close representation of my system - my clamp circuit comprised V1 (wall wart), R1, D1 and C1 - in the schematic R2 is the resistor which is on the royer circuit i was given, and I1 is intended to be the draw on the components (this max' out at 0.5ADC at the right output voltage)
I made the load intentionally tiny (10 mA), because i just wanted to get SOMETHING to work. My first instinct was that the load on the output was too much.
Looking at the transient analysis, there is some odd behavior at start-up, but then normal "zenering" action as one would expect.
So I increased the simulated load to 100 mA - and boom, it all went to <snip>. Interesting to me, but at least it made me feel less bad about my lab results.
One thing that i had played with in the lab, was changing R1 values - dropping R1 to a low value had made the circuit somewhat functional - but <snip> did that thing get HOT! I eventually used a 10Ω 25W resistor in the real world.
So in schematic 3 i did the same, dropped R1, and left the load high. The simulation showed the zener working, but the output voltage (red) going to <snip> still. <snip>
(continued on next post)
My plan for making the circuit as safe as possible was to clamp the input voltage such that the output could never rise above the required 500 VRMS.
I did some circuit characterization and found that at around 4.5-4.75V with a loaded or un-loaded output the royer oscialltor measured around 525-550 VRMS on a DMM.
Lucky me, a 4.7V zener is a common component - so i went about designing a simple input stage of components.
I came up with a circuit, and went straight to breadboarding it prior to simulation...breadboarding did not work - the clamp worked independent of the royer, and the royer worked independently of the clamp..but once i put them together neither part worked - and a lot of good components gave their life as i tried again and again. In the schematics i will post refer to the C1/R2 node, this point never went above 0.6VDC...i had no idea what was going on.
So i went back to simulation to try and see what was going on...the story begins here.
(note:
green trace = V1/R1 node
blue trace = D1/R1 node
red trace = C1/R2 node)
Schematic 1 was a close representation of my system - my clamp circuit comprised V1 (wall wart), R1, D1 and C1 - in the schematic R2 is the resistor which is on the royer circuit i was given, and I1 is intended to be the draw on the components (this max' out at 0.5ADC at the right output voltage)
I made the load intentionally tiny (10 mA), because i just wanted to get SOMETHING to work. My first instinct was that the load on the output was too much.
Looking at the transient analysis, there is some odd behavior at start-up, but then normal "zenering" action as one would expect.
So I increased the simulated load to 100 mA - and boom, it all went to <snip>. Interesting to me, but at least it made me feel less bad about my lab results.
One thing that i had played with in the lab, was changing R1 values - dropping R1 to a low value had made the circuit somewhat functional - but <snip> did that thing get HOT! I eventually used a 10Ω 25W resistor in the real world.
So in schematic 3 i did the same, dropped R1, and left the load high. The simulation showed the zener working, but the output voltage (red) going to <snip> still. <snip>
(continued on next post)
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