Delta Pulse

[Geo]

Hi Giovan.
You can use 32... 36 turns at a square 33cm coil
Regards

You need more more turns for a 33cm coil !!!!!!!
Calculate it for 800 ... 1000 uH

thanks

[Geo]

You must try to change the LF356 with a better IC .... as 5534, AD877 (if i remember ok) etc.

bad idea. NE5534 is not MOS-FET input stage Op Amp and will not working in DP. LF357 is really best then and novatime. please Geo do not mislead... in Delta you can use only MOS-FET opamps. another way you will get the trouble.

Basically was the different and better IC. I don't remember any type and i did not tried an other type. But after 20+ years i am sure that there are better ic's with lower noise and maybe better frequency cut off.
At ATiny4 i changed the LF357 with AD844 and results was great. Maybe why not and at DP?????

[kt315]

You must try to change the LF356 with a better IC .... as 5534, AD877 (if i remember ok) etc.

bad idea. NE5534 is not MOS-FET input stage Op Amp and will not working in DP. LF357 is really best then and novatime. please Geo do not mislead... in Delta you can use only MOS-FET opamps. another way you will get the trouble.

[Geo]

what is the best choice for increasing the Gain of DP , increase the gain of LF357 or add a secondary amplifire between LF357(IC 4) and TL062(IC5 A) ?

This is a big problem. If you will increase the gain then you will have more noise and worst performance. I tried with a second amplifier but without results. Also i changed the gain of LF356 ...7 and TL 0.. but without good results. So who is the solution ????
You must try to change the LF356 with a better IC .... as 5534, AD877 (if i remember ok) etc.
Regards

[Geo]

first i use a coil with 1*1 meter and 15 winding but it was very unstable , i remember that the commerical detectors use lesser winding , i got best performance and stability in 8 to 10 coil turns , maybe you're right but i do all of that in my home and my home is near a RF transmittal center and very noisy .

i should make a new coil with higher turns and check it out door in next weekend if the rain allow me

the first part of 556 D1A has 50% duty cycle when it's off the main gate to VCO D10C was open , why ?what happened if the gate was always on ?

Hi Alex. You make a big mistake.....
You cant check a 1x1 m coil in the lab there are alot of erratic signals. I can check in the lab only until 50x50 cm coil. If it is bigger then detector is very unstable.
What wire do you use at the 1x1 coil ????? For me it is good to be 1 mm at least.
Regards

[Geo]

Good morning, i build my coil with 15 turns, it has 33,5 cm x 33 cm , it has all in pvc, But the sensitivity depends too of values of resistors and calibrate of the Delta Pulse i have detected an money at 18 cm , 20 cm , it is the best with my delta pulse.




Thanks
----------------------
From Brazil

You need more more turns for a 33cm coil !!!!!!!
Calculate it for 800 ... 1000 uH

[Geo]

Try to use a 1mH coil. Original coil is 1.1 x 1.1 m 16turns. After coil construction you must play with damper resistor. If you leave the frequency at 100Hz then the existing 2k2 is OK.

[perdica 2]

better picture

http://www.servimg.com/image_preview.php?i=17&u=12558588

[perdica 2]

hi

i want to design big coil for delta pulse and i have simulated coil parameters
and i see changes in the pulse (like a self-oscilation) i don't now

can someone tell me whwt couse this changes like in the picture

https://www.geotech1.com/thuntings/attachment.php?attachmentid=7331&stc=1&d=1230151374

Coil

Good morning, i build my coil with 15 turns, it has 33,5 cm x 33 cm , it has all in pvc, But the sensitivity depends too of values of resistors and calibrate of the Delta Pulse i have detected an money at 18 cm , 20 cm , it is the best with my delta pulse.




Thanks
----------------------
From Brazil

[kt315]

Alexander, is it this pix CLEAR for you or not? can you RECONNECT your wires according the pix?
I see your elecronic skill is very low, you must read more technician books.

[Great_Alex]

first i use a coil with 1*1 meter and 15 winding but it was very unstable , i remember that the commerical detectors use lesser winding , i got best performance and stability in 8 to 10 coil turns , maybe you're right but i do all of that in my home and my home is near a RF transmittal center and very noisy .

i should make a new coil with higher turns and check it out door in next weekend if the rain allow me

the first part of 556 D1A has 50% duty cycle when it's off the main gate to VCO D10C was open , why ?what happened if the gate was always on ?

[kt315]

i use 1m *1m coil with 8 turn winding

try use standart coil for DP. 16 turns for 1m x 1m coil. you use absolitely improper coil and so get poor result. why you do all CONTRARY to common sense that the people had wrote here many times???

[Great_Alex]

I change the 2.2 K with 680Ohm and the device become more stable but the depth didn't differ too much cause it make me use of lower preamp gain, in higher gain the DP absolutely overshoot and didn't work .

i change the 20K PULSE WIDTH pot with 50 kilo for higher pulse width for greater depth , a good choice it increase depth slightly but the Battery scream Heellllllllppppppppp and then the IRF840 ( i use IRF840 instead of 740 ) smoked , what is the best choice for more powerfull Mosfet with lesser inner resistance that could absorb 600V shock of back EMF , i see the Transistor that used in MDL pictures that michael sent was very big and perhaps very powerfull , any body know what's that ?

what is the best choice for increasing the Gain of DP , increase the gain of LF357 or add a secondary amplifire between LF357(IC 4) and TL062(IC5 A) ?