Hi All:
I'm new here so hope I'm in the right place..... As part of a larger project ( Computer P.S. for bench top power ) I thought it would be fun to include some square and sine wave signal sources ( 1Khz, 10khz, 100Khz, 1Mhz) using 555 timers which I have more than a few of. These 555 timers ring like the bells of St. Marys. My question is about the 100 Khz design.
After some experimentation, I've got an acceptable square wave output from the 2N3904 emitter follower. Adding C2 (top of page) connected directly to pin 8 (555) helped a lot. Also the 9.1v zener in series with the 1N4148 helped. I still see some ringing on the sine wave output but various attempts at filtering the sin wave are not helping.
I was wondering if anyone has a suggestion for how to make the sine wave cleaner. The ringing seems to be in the 1-10 Mhz range ( near as I can tell on my trusty old B&K 30Mhz scope ). Maybe a series tuned circuit across the output of the 2N2222 ? I don't have a lot of inductors to experiment with. My technician level education is bit old (1970's) maybe something new is out there. Thanks
I'm new here so hope I'm in the right place..... As part of a larger project ( Computer P.S. for bench top power ) I thought it would be fun to include some square and sine wave signal sources ( 1Khz, 10khz, 100Khz, 1Mhz) using 555 timers which I have more than a few of. These 555 timers ring like the bells of St. Marys. My question is about the 100 Khz design.
After some experimentation, I've got an acceptable square wave output from the 2N3904 emitter follower. Adding C2 (top of page) connected directly to pin 8 (555) helped a lot. Also the 9.1v zener in series with the 1N4148 helped. I still see some ringing on the sine wave output but various attempts at filtering the sin wave are not helping.
I was wondering if anyone has a suggestion for how to make the sine wave cleaner. The ringing seems to be in the 1-10 Mhz range ( near as I can tell on my trusty old B&K 30Mhz scope ). Maybe a series tuned circuit across the output of the 2N2222 ? I don't have a lot of inductors to experiment with. My technician level education is bit old (1970's) maybe something new is out there. Thanks
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