Delta Pulse

[hawk17966]

Thank you!


Thank You, Carl!

But still not clear; can i use lower resistance coil than without risk to warm fet or even get it hot and blow?

"To reduce coil current, you need to add a few ohms of resistance in series with the coil."
That resistance should be resistor but high power (5w,10w) or 1/8w or simillar? Or does'nt matter?

Pulse Star II machine used with coil 2 ohm resistance and high power in it does'nt blow fet, but Delta Pulse even with 3-4ohm coil a less power blows fet?? How come? Even freqency is lower (150Hz) than at PSII...???!!!
:confused:

[Carl-NC]

You need to be careful with power, and it's not straightforward in a pulsed circuit. Looks like the coil gets a full 24V, so let's say we run 150Hz (T=6.7ms), a 4 ohm coil, and a 335us pulse width (5%). The IRF740 has 0.55 ohms of R-on, so during turn-on it sees 2.9V and 5.3A. This is 15.37 watts, but only for 5% of the time. For the remainder, the FET is off, so the time-averaged power will be 770mW. This should not be a problem, but only if during the OFF time there is sufficient heat sinking to keep the FET cool. If not, then the temperature will rapidly climb toward the 15 watt level, and possibly blow the device.

You can do the same calculations for a series resistor, and probably find that you need at least 1W, probably with heat sinking.

[hawk17966]

Many thanks!


Many thanks Carl!
It will help me.
In PS II i noticed that there is no any heat sink on fet? Coil resistance as i said before is 2 ohms...About resistor i am not shure of proper value..
In delta Pulse pretty simillar but coil shoul nod be under 6 ohm....because than fet is warm,hot even blows...!?
As you see i am not expert in those things...i would like to learn more and understand more, but since do not have some elementar knowldege....."tech-language" sometimes confuses me.....

[Carl-NC]

I don't know about the PSII... maybe the coil only sees 12V, not 24V... maybe the pulse width is shorter.

Use whatever resistor value keeps the coil+resistor above 6 ohms. Also heat sink your FET.

[hawk17966]

What 24v ...?

:confused:
What 24 volts are you talking about Carl? D.Pulse uses only one 12v accu.
same as Pulse Star II....
Sory if i bug you, but my DP is working average,i would like to improve it if it is possible....
Thanks

[Carl-NC]

In looking at the schematic posted in this thread, it shows +12V on the coil and -12V on the switch, so that would be 24V across the coil. However, in looking again, that doesn't make sense per the way the preamp is powered. I haven't read this whole thread, so maybe this is an error that has been discussed.

[okantex]

what is the value of current in amphers in coil for delta pulse and approximately for other detectors

[Unregistered]

Are coaxial the cabble betwin coil and detector?

Hi:
This is my first cuestion (title cuestion) and whats the best PI detector, is delta pulse?
and whats the best discriminator detector project? is bandido?.
thanks a lot.

Luis Miguel.

[Geo]

In looking at the schematic posted in this thread, it shows +12V on the coil and -12V on the switch, so that would be 24V across the coil. However, in looking again, that doesn't make sense per the way the preamp is powered. I haven't read this whole thread, so maybe this is an error that has been discussed.

Hi. The voltage is 12V. +12 and -12v are the + and - polarity of the 12V battery.

[Geo]

But still not clear; can i use lower resistance coil than without risk to warm fet or even get it hot and blow?

"To reduce coil current, you need to add a few ohms of resistance in series with the coil."
That resistance should be resistor but high power (5w,10w) or 1/8w or simillar? Or does'nt matter?

Pulse Star II machine used with coil 2 ohm resistance and high power in it does'nt blow fet, but Delta Pulse even with 3-4ohm coil a less power blows fet?? How come? Even freqency is lower (150Hz) than at PSII...???!!!
:confused:

Hi Hawk..... You can use a low resistance coil without the risk to warm if you connect in series a resistance 2...8 Ohm. A resistor with power 2W is O.k
I tried a 2 Ohm coil with 2.7 ohm 1W resistance in series at my D.P without any problem.

[Unregistered]

U2 & U3

Hi all,
Can I use MC14538 instead of CD4053?

[Unregistered]

U2 & U3

Hi all,
Can I use MC14538 instead of CD4538?

[1843]

CD4538

Hi all,
Can I use MC14538 instead of CD4538?

Hi,
This is my question too.

[nelson]

Delta Pulse schematics

Hi kt315.
Do you have the schematics for delta pulse that you made on sprint layout pcb file. I had already made the pcb from your file on sprint layout software, but i had found some differences when i compare it with the schematics made on ISIS software.
Sorry for my english and i ll be waiting for your help
In advance many thanks.
Regards
Nelson

[1843]

SprintLayout Pcb

Hi kt315.
Do you have the schematics for delta pulse that you made on sprint layout pcb file. I had already made the pcb from your file on sprint layout software, but i had found some differences when i compare it with the schematics made on ISIS software.
Sorry for my english and i ll be waiting for your help
In advance many thanks.
Regards
Nelson

Hi,
I made that, but it does not work.
How should be Waveform of Tr6 and TR7?
Best regards