Tweet
Looked up the data sheet . For frequency it said up to 10MHz . For AC volts it said average based on RMS sine wave 40 to 400 Hz . Maybe I need a new meter . I need a whole new thread for my scope ! Those voltage drops are not even close to 30% . It is enlightening to see how far from the corner it has effect . I would like to think going the other way it reaches 0 . The grid stopper and Miller effect are also at work so all that RF should be stamped out before all that gain . I should also mention I used the formula from the RCA receiving tube manual to calculate gain with 1M5 and 250k following grid resistance . I got 54 and 47 . The numbers are different but the degree of drop is proportional to our results so I think the loading explanation is valid . Now I need to build a head case . Any recommendations on a DMM ?
-
-
Specs are fun, but are not brick walls. My old 35MHz scope served me well for audio. But I occasionally serviced wireless microphones, which operated at something like 170MHz. If I wrapped a piece of wire around the transmitter pack, clipped my scope probe to it, and ran the vert sensitivity all the way up. I could just see a waveform when I activated the transmitter. It wasn't much, but it was enough to see that the transmitter was sending out an RF signal.Education is what you're left with after you have forgotten what you have learned.Comment
-
Tube gain drops with lower supply voltage (and with tube age).Originally posted by 35L6 View Post
The 68k input grid stopper together with the Miller capacitance (around 150p) constitute a low pass filter with a corner frequency around 16kHz.
The Miller capacitance of the second stage effectively adds something like 80p to the 100p plate to cathode cap with vol. fully up.
For frequency response and phase measurements/plots up to 1Mhz I'm happy with my Velleman PCSU 200 USB scope, which has an integrated synchronized signal generator and Bode plotter function.
- Own Opinions Only -Comment
Comment