Hello I'm currently trying to complete the p3a amplifier, and trying to find a good input capacitor, I found 20 in my drawers and tested the on my oscilloscope, it has frequency response analysis, all are tested under same conditions and same load, 22k.
I'm having trouble interpreting the grafs, would appreciate some input, first time I've used this function.
Ps highest uf values first
I'm having trouble interpreting the grafs, would appreciate some input, first time I've used this function.
Ps highest uf values first
Haven't tried that but just realized that I specified load impedance, but not the actual input impedance which should be 240r measurements are performed with 50 ohm input loading
Input impedance is 22k.
All that is needed is a good quality bipolar 4.7uF at 50V.
But something is your measurements cuts off the bass way too high.
Check the scope setting first.
All that is needed is a good quality bipolar 4.7uF at 50V.
But something is your measurements cuts off the bass way too high.
Check the scope setting first.
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The red curve is the phase, the blue curve the magnitude. In any case, there is something causing larger errors than some of the devices under test.
Is there a way to calibrate out the response with a shorting wire?
The input capacitor cannot be shorted out, due to the bipolar input stage.
Try a loopback test without the amplifier in the circuit at all.
Why is the gain -20dB then? Probably an instrumentation error.
Try a loopback test without the amplifier in the circuit at all.
Why is the gain -20dB then? Probably an instrumentation error.
Make sure that your scope coupling is on DC not AC coupling.
Most O-scopes tend to roll off like that on AC coupling.
Most O-scopes tend to roll off like that on AC coupling.
It is with some shame I must tell that you gents were correct, it looks strange, we had guests yesterday, but checked everything today, calibrated probes etc, problem was that my probes have x1 x10 switch on the handle and I by accident had one probe on x1, that corrected gain and phase follow like they should.
This thread is useless to anyone and hope moderator will delete it.
Leasson learned, if it looks off check twice.
This thread is useless to anyone and hope moderator will delete it.
Leasson learned, if it looks off check twice.
In the mean time you can edit post #1 (the only one we can as a thread starter) of this thread and put in bold format at the beginning something like «thread to be deleted » ….