Beachmaster Digital

[Olly]

hi，The master! In all PI detector circuits, large electrolytic capacitors are used in the power supply part, which increases the volume of the circuit board. We have high current battery power supply, do we necessarily need large capacitors

The 1000uF electrolytic with low ESR is required for C27 as this offloads the heavy current transients from the battery -12V supply.
The value of 1000uF was chosen such that with a 100uSec wide pulse and a flat top current of 2A we'll drop a maximum of 200mV during a TX pulse.
This is according to the formula "I/C = dV/dT"

The bulk decoupling capacitors C13 and C16 are there to compensate for the lead inductance of the wires which run from the battery to the PCB.
If you use thick wires and have the batteries very close to the board, then you can most likely get away with having smaller capacitors.
If on the other hand, you mount your batteries under the cuff as I do and have relatively long wires to the PCB in the control box then the 1000uF caps are required.

[jeep6789]

hi，The master! In all PI detector circuits, large electrolytic capacitors are used in the power supply part, which increases the volume of the circuit board. We have high current battery power supply, do we necessarily need large capacitors

[Olly]

Is Mur860 to reverse, should it be placed between the S pole and -12?

No, it's correct where it is, its purpose is to decouple the Mosfet Coss from the coil and facilitate a faster flyback falling slope.
The MUR460S would probably be a slightly better choice as it's max reverse recovery time is a bit quicker but the 860J seems easier to find in SMD.

[jeep6789]

Is Mur860 to reverse, should it be placed between the S pole and -12?

[Qiaozhi]

Gee, you sound just like my old boss!

Haha! I was thinking the same thing.

[jeep6789]

Because everyone is waiting for your news, I hope you must succeed, refuel

[Olly]

What's the holdup? Did the project fail

Gee, you sound just like my old boss!

This is a hobby project which I’m pursuing at my own pace so you’re just going to have to be patient I’m afraid.
They say that all good things come to those that wait ��

[jeep6789]

What's the holdup? Did the project fail

[Carl-NC]

Search the forum for "bipolar PI". Include the quotes.

[jeep6789]

What is a bipolar PI

[Carl-NC]

Beachmaster (and any mono-polar PI design) has single-ended sensor so a differential amp won't help. However, we can take a late sample and subtract it to suppress interference. This is another form of differential amplification.

[jeep6789]

Regarding the amplification of the premium, why no one is differential amplification? Differential enlargement can resist interference

[MartinB]

Hello! I want to make a wireless detector with Bluetooth and single-chip mechanism, because the op amp is required to ? 5V level, single-chip microcomputer and Bluetooth 3.3V, then in this circuit, how should I generate ? 5V and 3.3V?[ATTACH]57089[/ATTACH]

Hi jeep6789,
You just need to extend your main board or build a small board with regulators that will give you power in; +12v, -12v, 5v and 3.3v out.

[Olly]

Hello! I want to make a wireless detector with Bluetooth and single-chip mechanism, because the op amp is required to ? 5V level, single-chip microcomputer and Bluetooth 3.3V, then in this circuit, how should I generate ? 5V and 3.3V?[ATTACH]57089[/ATTACH]

Perhaps these queries should be in a thread of their own?

[Olly]

I need to get the level of level A, please help，Thankyou

I would suggest downloading and using LTSpice for some circuit simulation. That way you can get a reasonable idea of what the analogue section of your circuit is doing.

Regards