Delta Pulse

[kt315]

pls can you post other Pictures with better contrast of tracks and mass plane can only see pinky light red and red
i am interested to adapt your design to sprint layout, any gerber files can help too
thx

ufff,,, i am not able to delete top silk layer... write me what color you prefer for silk and i ll remake.

top.rar

[Xtrem]

Hi kt315, check the mod, if you "see" carefully ,you see the opportunity to make very easy a 24V Version, you need then only a 7912 for the whole circuit(exept 556 and mosfet) a 7812 (for 556 timer driver) and a little circuit that connect the 556 to 4538 and 4066 (level shifter) ...4 or 2 transistors, i did not try the 24V version.

[kt315]

thank you Xtrem for nice suggestion. i will check your mod and will do changes in the layout in following batch (you know maybe new batch ordering only to every new year LOL!)

[bernte_one]

[ATTACH]37789[/ATTACH]
[ATTACH]37790[/ATTACH]

pls can you post other Pictures with better contrast of tracks and mass plane can only see pinky light red and red
i am interested to adapt your design to sprint layout, any gerber files can help too
thx

[Xtrem]

Dont burn the Diodes, and better switch off the mosfet...
Connect the pin 7 of 556 DIRECT to -BATT, not to -E,
C1 and C3 too.
From pin 9 (out 556) dont connect direct to pin 5 (input 453 ,but trough resistor 6K8,
so there are no problem for the 4538 , if you connect direct you will burn the 4538.
So Delta Pulse is modificated to ...normal operation.
Sorry about my English, im too lazy to use translator today..
greetings from Greece.

[chevesne]

We have to respect the keyway of the socket.

[kt315]

diodes, or one of two, burn ALWAYS if at least one chip is setted backward. people solder sockets for ICs and do not
see top silk marking on a board. that is why i do not suggest to solder sockets.

[eclipse]

The diodes provide small offset voltage (~1.4V) for the middle point voltage (GND) so you have 12V - 1.4V = 10.6V / 2 = 5.3V for +E; -5.3V for -E
So they don't protect anything. If you have limited the pulse width to let say reasonable number 350-400us it will probably be okay for years of usage.
I've managed to burn the diode (414 on probably 5th usage (and on the field!, 50km away from home not able to de-solder anything) with 1 meter dug hole on strong signal.
Mosfet was fried like shish-kebab. Imagine the disappointment.

[kt315]

if the diodes burn off then MOSFET turns in open state and immediately grills up before a solder melts on pins' pads (+300C).
i do not think that they are used for protection...

[ivconic]

Finally people are realizing this flaw.
This diode (4148 burns easily, even good brands fail (may happen when you leave width (pulse width) rotated all the way up to 500us and then you switch on the power).
Just use higher power diodes, I'm using 2 x MUR120.

I think those two are supposed to be exactly 1N4148 and serves there as sort of "protection".
They supposed to burn fast and protect the rest of circuitry in case if something goes wrong.
I never really counted; but i think that i made 70-75 Delta Pulse diys so far and ONLY ONCE i had case one of those two to burn.
I am afraid in case if 1N400x is put there and if something goes wrong; the rest of circuitry will be pretty much trashed out.
Since Delta Pulse is mostly made by hobbyists and in huge percentage on pcb design posted by KT315 long time ago (my most favorite pcb); most probably the huge majority of those diys are made on double sided boards BUT without metalized vias and holes; therefore all the components with soldering pads on both sides are soldered also on both sides.
I can't imagine the "pain" to remove some components soldered like that in case something goes wrong!
That's why is better to have easy approachable "weak point" which will break first in such cases and later been easy replaceable.
But i could be wrong too...

[kt315]

1N4001-1N4007 are popular everywhere. what you have under hand set them... any 0,5-1 ampere diodes...

[eclipse]

Finally people are realizing this flaw.
This diode (4148 burns easily, even good brands fail (may happen when you leave width (pulse width) rotated all the way up to 500us and then you switch on the power).
Just use higher power diodes, I'm using 2 x MUR120.

[kt315]

take attention on VD8 VD9, i change them on another diodes with more power... chinese 1N4148's are sometimes not so good, burning, and create problems, for beginners.

[kt315]

i call first pulse delay by DISC but it is not disc in real, i must adapt all terminology on kitchen wifes level, level zero, just as mainly

customers have zero level in the electronics.
in real this is distinction small-big. for big target increase first pulse delay to 120us and more. experiment on what you have and what you want to find up.

frequency here does nothing. that is not same detector kinda where you can get advantage on freq increasing, 120 or 300 Hz does not have a value.

[mschmahl]

How to set up Delta Pulse (kt315 version) for big metall, over 20 cm diameter. I´m interested in pulse wide, Frequency (think 120 Hz), first pulse delay,...
I use a 1x1 m coil.