DIYEFI.org Forum

Actually, the output impedance of almost all audio amplifiers is approaching zero and for good reason. Very good point Fred :) The output has to be as low impedance as possible to damp the mechanical motion of the speaker cone otherwise the speaker will oscillate back and fore like a right lemon ca...

This is audio frequencies we are talking about here and only a specific narrow band within that range, I really don't think we'll need to worry that much about impedance matching. This isn't RF and we are no where near the kind of design considerations required for it. The Piezo knock sensors in my ...

For the R1 and R2 values that set the gain of the internal front end amplifier it's a ratio of R1 to R2 so for a gain of x10 R1 = 1K and R2 =10K and the same in reverse for /10 attenuation R1 = 10K and R2 = 1K. From the signal levels on my laptop (roughly 800mV P-P for the knock) I would suggest x10...

I've connected the knock sensors directly to the sound card on my laptop while playing with MS2 and while there is a bit of noise on there the knock signal is clearly visible and I put it down to the sensor bandwidth. The other regular noises picked up are the valves slamming into the seats, piston ...

Err???? looking at the data sheet xin and xout are to do with the timing crystal for the on chip clock. The addition of a crystal and 2 caps to ground off of xin and out will provide an on chip time base. The internal symbol is that of a NOT gate or inverting buffer. The Xin probably has a tap off i...

The TPIC8101 / HIP9011 is on my board, well, will be in the next turn. I saw it as a easy path to basic knock sensing. Delayed now since I got the layoff. Have time but funds are tight. The wife would have a fit if I spent on PCB's now. Cylinder by cylinder knock sense may be massive over kill. I a...

I'm totally gutted that I couldn't come to your 30th. :( Probably a good thing though otherwise I would have spilt wine over her too, just to see if I got away with it. lol I know what you mean about the Spanish way, its fantastic, after taking holidays to the Costa del Sol area and Fuerteventura I ...

Here's my effort.
Not quite sure about the copyright on the TA card photo, maybe the TA guys wouldn't mind a little free advertising

Awesome!