|
LOL. I wouldn't?call it "disagreeing". ;-) I'm still trying to figure out exactly?why I am seeing what?I am. Which is that Pin 3 goes negative with my P48 mics with?how I am wiring them. My OPA mics respond with a positive pressure spike into the diaphragm?causing?a positive increase in the voltage on Pin 2.?I am biasing the capsule with a Positive voltage?on the backplate of the capsule. When the diaphragm?moves towards?the backplate the distance goes down, increasing capacitance. charge remains?constant thus the magnitude of voltage across the?capacitance?goes down. Because the?backplate is constant "+" voltage the?net effect?is the?voltage on the diaphragm?goes up. I see this. My circuit is a non inverting?buffer to pin 2.? Now with the Electret capsule I suspect that the charge is negative compared to the biasing of my U87 and my OPA mics. I haven't?built a test setup yet to determine?that. When positive?pressure comes into the capsule, the?internal fet conducts more, causing the voltage on the "+" lead of the capsule to go negative. Which is why connecting to pin 3 seems to work.? Jules On Mon, Jan 1, 2024 at 6:50?PM Richard Lee <ricardo@...> wrote: I'm also noticing about half of the documentation involves a Capacitor to Pin 2 with the "hot lead" to Pin 3, whereas the other half involves a Capacitor to Pin 3 with the hot lead to Pin 2.cx_b, are you using the latest 28nov23 version of SimpleP48.pdf in my Files? --
Best Regards, Jules Ryckebusch 214 399 0931 |
