First impressions: unorthodox drawing style, Ic-q2 is summing of only base currents from q2 and... another q2? There are six q2's!. How to calibrate the attenuators and the separation pots? Purpose of S2? Frequency range with R9? Assume that all connectors shown are banana-style - BNC is preferred. Other issues pending.
Your schematic is great.
My last project was a VTVM using a chip instead of a tube and from command parts. But did take months to work out little problems.
All parts was purchased from Amazon or Walmart.
This is simpler it just switching signals.
Adding the cellphone to switch will help anyone that does buy a Oscilloscope
The switching rate can as little as 20Hz to way over 10KHz.
At 10KHz give somther view compared to 5KHz. At 20Hz give two different views.
If Q2A is ever turned on it will fry along with Q2E. That's probably not what you want...
Instead of the multiplexing, why not just use the L and R channels of the phone and the two channels of the scope?
Tom
40 kHz on a cellphone?? That would surprise me. POTS was limited to 4 kHz as I recall. Same for GSM as I recall. I would expect the microphone to be sampled at 44.1 kHz or 48 kHz at the most. I'm willing to be proven wrong, though.
Instead of the multiplexing, why not just use the L and R channels of the phone and the two channels of the scope?
Tom
There are a lot cellphones only have one channel.If Q2A is ever turned on it will fry along with Q2E. That's probably not what you want...
40 kHz on a cellphone?? That would surprise me. POTS was limited to 4 kHz as I recall. Same for GSM as I recall. I would expect the microphone to be sampled at 44.1 kHz or 48 kHz at the most. I'm willing to be proven wrong, though.
Instead of the multiplexing, why not just use the L and R channels of the phone and the two channels of the scope?
Tom
Dave
Ah. Good point.
Now going back to your circuit: One idea could be to make the two inputs differential and switch the current source for the diff pairs back/forth. I've done that in the past and it worked pretty well. Another option could be to use transmission gate switches, such as the 4066 CMOS analog switch.
Tom
Now going back to your circuit: One idea could be to make the two inputs differential and switch the current source for the diff pairs back/forth. I've done that in the past and it worked pretty well. Another option could be to use transmission gate switches, such as the 4066 CMOS analog switch.
Tom
Here more update schematic showing resistors to protect the transistors from overloa
My last project had ups and downs too.
It is a simple amp and switch combo.
If look the old tube type they used very few parts and is a just a amp and switch
Dave