I'm trying to build a 4MHz square wave oscillator as part of a solid state tesla coil--the oscillator is shown at the bottom left of the following schematic (bottom transistor is tied to 12V): http://uzzors2k.4hv.org/projectfiles/4MHzclassE1/proper_4MHz_classE_SSTC.gif
The first picture is a scope reading where the base of the top 2N3904 would be (I had not soldered in any transistors at this point). As you can see it is already quite ringy.
The second picture is a reading at the same point after soldering in the transistors. I'm not sure I understand why the majority of the signal is now negative?...
Finally the "4 MHz Drive" output is shown in the last picture, with no load attached (ie I haven't soldered the next transistor stage). What could cause such a distorted waveform?
Other information:
--I am using a 20MHz oscilloscope
--The circuit is powered by the +12V rail of a computer PSU. I put a 470uF capacitor across the supply on my circuit but it only helped suppress the ringing slightly (as shown).
--I used a tiny surface mount 180pF capacitor before the base of the 2N3906. Are these easy to damage with normal soldering irons? The first time I attempted soldering it I messed up and had to resolder it...
--I attached a screenshot of the PCB layout I made.
The first picture is a scope reading where the base of the top 2N3904 would be (I had not soldered in any transistors at this point). As you can see it is already quite ringy.
The second picture is a reading at the same point after soldering in the transistors. I'm not sure I understand why the majority of the signal is now negative?...
Finally the "4 MHz Drive" output is shown in the last picture, with no load attached (ie I haven't soldered the next transistor stage). What could cause such a distorted waveform?
Other information:
--I am using a 20MHz oscilloscope
--The circuit is powered by the +12V rail of a computer PSU. I put a 470uF capacitor across the supply on my circuit but it only helped suppress the ringing slightly (as shown).
--I used a tiny surface mount 180pF capacitor before the base of the 2N3906. Are these easy to damage with normal soldering irons? The first time I attempted soldering it I messed up and had to resolder it...
--I attached a screenshot of the PCB layout I made.
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