Delta Pulse

[Max]

Hi All.
Delta Pulse don't work with 6V. It has in series with power suply two diodes so the voltage will be 6-1.2=4.8V,very low voltage. If you modify the circuit.... who knows...maybe to work. When the voltage is lower than 9V the detector is unstable and has very low sensitivity.
Bye

Hi Geo,
yes there are the 2diodes for op amp supply...like in xr-71 and it cannot work at 6 volts with original op amps I think...but using e.g. tlc2262 it could cause these devices require less supply voltage instead of tl0x2 types.
Also other things could do the job I think, like:
TLC2252
TS272
TS27M2
TS27L2
MC33178
LS204
Anyway I've never tested...just my hypotesys. For other components it's not a problem having less supply voltage (cmos, 555 etc).
Instability is due to nearing of saturating voltages with useful signal...then when signal increase we can easy have saturation on op amps.
With rail-to-rail (e.g. 2262) problem is well reduced and you haven't any istability. Also consumption is much lower...than with TL0x2 series.

Best regards,
Max

[Unregistered]

hi
I have adaptor with these features
input: 220V 50Hz
power: 9W
current :500mA
output:1.5 V , 3V , 4.5V , 6V , 7.5V , 9V , 12V

can I use it to test delta pulse.if it is working or not?
is 500mA changing while changing voltage?
okantex

[okantex]

btw since I do not know tecnical terms of electronic .I want to write the things on my battery

6V-4.5Ah/20HR
constant voltage charge
voltage regulation
cycle use........................:7.35-7.5V
stanby use.......................:6.75-6.85V
max. charg,ing current...........: 1.35A

does this cysle use hhave any meaning for more than 6V .

can we think 7.5 -1.2 =6.2 bigger than 5V and enough for delta ?

[1843]

The two PS diodes for what reason have used? They cause that gate driver voltage (S-G) be between 1.5 to +VB...
Is it better that we short them?

Regards

[Max]

btw since I do not know tecnical terms of electronic .I want to write the things on my battery

6V-4.5Ah/20HR
constant voltage charge
voltage regulation
cycle use........................:7.35-7.5V
stanby use.......................:6.75-6.85V
max. charg,ing current...........: 1.35A

does this cysle use hhave any meaning for more than 6V .

can we think 7.5 -1.2 =6.2 bigger than 5V and enough for delta ?

Hi okantex,
current is not regulated in your supply so it depends on voltage applied and load (ohm's law).
Battery is a gel-lead-acid type , that I know well...and could be used on this kind of circuits with success...due also to low internal resistance...but is heavy for my taste.
Anyway...voltage accross battery vary from full charge state to full discharge...but you can use it. Just you need some adjusting on threshold when discharge causes your detector go out of tune...say every ten minutes or so...
I've used many 12V 4aH and 12V 1.3ah on my pulse induction devices...works good but the more the current capacity the more the weight.
I suggest to buy a battery that could cover 6-8 hours of detecting maximum...or buy more than one and the changing them when discharged on the field...6V 4.5 AH could be heavy to transport e.g. hip-mounted. Anyway...It's your choice.

Just put on the supply lines a fuse of 500mA FAST to avoid problems if reversing wires...to save electronics ! Better would be a limited current power supply for testing...but some are expensive lab devices...

Best regards,
Max

[Max]

The two PS diodes for what reason have used? They cause that gate driver voltage (S-G) be between 1.5 to +VB...
Is it better that we short them?

Regards

Hi,
what's important is gate Vgs fall time...not a real problem to have some volts under Vgson...if this is the question.
Other important issue is that fet is fully turned on at +VB and this is the case here at 12V.
For 6v operations one could use a lower Vgson device with same transcapacitance.

Best regards,
Max

[okantex]

Hi Max
""
Anyway...voltage accross battery vary from full charge state to full discharge...but you can use it. Just you need some adjusting on threshold when discharge causes your detector go out of tune...say every ten minutes or so...
"""
I could not understand what you mean.
do not you tune your detector at every 2 minutes.
do you mean something else?

""
6V 4.5 AH could be heavy to transport e.g. hip-mounted. Anyway...It's your choice.
""
my battery is something like 1 kg .no more.I am sure your 12v is heavier than mine.
I am not sure if it can drive ICs .after GEO 's words.
I looked datasheets of IC .they say supply voltage is +-15 or +-18
but we use them at 12V .this is also a big quessstion in my mind.

A friend say .he used 7v .his coil was 45 turn ,60cm diametre ,0.8 wire.
I tried to calculate inductance it was 3000microhenry?????
does not it be something like300mh?

""
Just put on the supply lines a fuse of 500mA FAST to avoid problems if reversing wires...to save electronics ! Better would be a limited current power supply for testing...but some are expensive lab devices...
"""
what is supply lines ? as ı said I am not electronition.just hobbiest.
can I charge my buttery with my adaptor .I gave it's properties at previous mail.
thanks

[Max]

btw since I do not know tecnical terms of electronic .I want to write the things on my battery

6V-4.5Ah/20HR
constant voltage charge
voltage regulation
cycle use........................:7.35-7.5V
stanby use.......................:6.75-6.85V
max. charg,ing current...........: 1.35A

does this cysle use hhave any meaning for more than 6V .

can we think 7.5 -1.2 =6.2 bigger than 5V and enough for delta ?

Hi okantex,
about your battery...what simbols means (BATTERY TRAINING):
6V-4.5Ah/20HR
constant voltage charge
voltage regulation
cycle use........................:7.35-7.5V
stanby use.......................:6.75-6.85V
max. charg,ing current...........: 1.35A
means that battery requires constant voltage charging, in cycle use voltage from 7.35 to
7.5 volts can be used...that means that if the battery is cyclically charged discharged
frequently you can use that voltage e.g. 7.35V to get it fully charged.
In standby mode...like in emergency lamps...where the battery stay charged for long time
6.75-6.85 voltage is used to keep the battery charged and avoid self-discharging due to
internal leaks- you are not interested in standby charging (so called...trikle-charging).
You need a full charged battery then to discharge due to using your metal detector and then
recharge it...it's CYCLE USE.
So you need to charge from 7.35 to 7.5 volts constant Voltage.
max. charg,ing current...........: 1.35A means you can't go over this value without damaging
your battery...avoid more current also because hydrogen is produced internally and battery
could explode at higher charging current - very dangerous, don't do that.
You need to provide enough current for enough time
example: at 1.35A you charge the battery in about 3.333 hours (4.5AH/1.35A).
I suggest using 1/10 of capacity current for 10 hours: 450mA (at constant 7.5volts !) and you
need some constant current charger to do that (you can find schematics on google: "charger lead acid lm317").
Or also better 300mA for 15hours. The longer the time...the longer lifetime of device and less
troubles...and also better charge at constant voltage cause hydrogen is adsorbed or expelled safely from the
battery (on some types there is an automatic hidden valve that do it).
20HR means that battery discharge is related to current delivery...
example: 4.5AH/20H --> 225mA is the maximum current you can draw from it without losing some battery
capacity...actually you can draw more with a 15-20% reduction of total capacity due to losses.
If current is too hi...you damage the battery and if shorted it could , again, explode.
You can also try to charge the battery using a normal unregulated supply...but I think it's not a good idea...
cause you need some limitation to charge it safely.
"does this cysle use hhave any meaning for more than 6V ."
When you have a fully charged battery you get a little mre than 6Volts...it's normal to have cause the cells
gives more voltage : a lead-acid cell is of 2Volts nominal...but you can get from 2.05 to 2.125 when fully
charged then you could have something like 2.125*3 = 6.375 volts at full charge...simply doesn't matter !
When a single cell go under 1.8volts it's fully discharged...so if you get
1.8*3 = 5.4 volts...you battery is game over and need recharging.
"can we think 7.5 -1.2 =6.2 bigger than 5V and enough for delta ?"
Your 6V battery cannot gives 7.5 volts even if fully charged. If so...battery is damaged and you need new one.
you have 6-1.2 = 4.8 volts: that 1.2volts is enough for many devices to read signals and stay away from
saturation, cmos and 555 would work fine too.
Real problems could be:
- Vgson for mosfet device (usually 4volts are enough to fully turn on but not always)
- lower audio volume (cause you have less vcc)
but most important is:
- OP AMPS polarization...supply : some devices don't like lower voltages...you need low
supply op amps like tlc2262 or , easy to find, e.g. lm358 to solve that problem. Usually a
single supply op amp could work at lower supply than dual supply devices... e.g. LM358 can
do it, better e.g. NE5532 (lower noise)...but better than everything is having rail-to-rail op amps there
cause also tl062 could work...but can be unstable in these conditions where saturation voltage
is too near useful signal level.
So, you can use tlc2252,tlc2262, ts27m2, ts27l2, mc33078, mc33178, ls204 instead of originals.

Best regards,
Max

[Max]

Hi Max
""
Anyway...voltage accross battery vary from full charge state to full discharge...but you can use it. Just you need some adjusting on threshold when discharge causes your detector go out of tune...say every ten minutes or so...
"""
I could not understand what you mean.
do not you tune your detector at every 2 minutes.
do you mean something else?

""
6V 4.5 AH could be heavy to transport e.g. hip-mounted. Anyway...It's your choice.
""
my battery is something like 1 kg .no more.I am sure your 12v is heavier than mine.
I am not sure if it can drive ICs .after GEO 's words.
I looked datasheets of IC .they say supply voltage is +-15 or +-18
but we use them at 12V .this is also a big quessstion in my mind.

A friend say .he used 7v .his coil was 45 turn ,60cm diametre ,0.8 wire.
I tried to calculate inductance it was 3000microhenry?????
does not it be something like300mh?

""
Just put on the supply lines a fuse of 500mA FAST to avoid problems if reversing wires...to save electronics ! Better would be a limited current power supply for testing...but some are expensive lab devices...
"""
what is supply lines ? as ı said I am not electronition.just hobbiest.
can I charge my buttery with my adaptor .I gave it's properties at previous mail.
thanks

Hi okantex,
"I could not understand what you mean.
do not you tune your detector at every 2 minutes.
do you mean something else?
"
Yes. Not 2 minutes but 10-15-20minutes YES. Because (this is a fact) both xr-71 and deltapulse haven't any internal voltage regulator...so VCC that is the battery level vary with discharge of it.
Actually I have on mine...voltage regulators but this is another story...in posted schematics there isn't so you need to retune sooner or later. The bigger your capacity of battery, the slower the discharge at a fixed current the longer it takes to need threshold adjust.
Actually I don't need to adjust periodically now...but I've done before using original schematic and 1.3 AH 12 V battery.
"my battery is something like 1 kg .no more.I am sure your 12v is heavier than mine.
I am not sure if it can drive ICs .after GEO 's words.
I looked datasheets of IC .they say supply voltage is +-15 or +-18
but we use them at 12V .this is also a big quessstion in my mind."
You are lucky...some of my batteries are heavier but also 1Kg is heavy for me...anyway...I'm lazy on that point!
Well...+-15 or +-18 are absolute maximum ratings...means that over that you burn your devices...
Actually you can use them on lower voltages e.g. +-5 or also +-3 or less.
For instance mc33178 could work very happy at+-2.5 volts and there are even lower supply devices (some works on single 3 volts and even less!).
"A friend say .he used 7v .his coil was 45 turn ,60cm diametre ,0.8 wire.
I tried to calculate inductance it was 3000microhenry?????
does not it be something like300mh?
"
Could be. I told you that only some components could require attention to work at 6V or be substituted. Must be 300uH.
"
what is supply lines ? as ı said I am not electronition.just hobbiest.
can I charge my buttery with my adaptor .I gave it's properties at previous mail."
Well yes...you can but you risk to damage it in charging. Supply lines = the positive or negative wire from your battery to the circuit - put the fuse there on one of these wires.

Hope this helps.

Best regards,
Max

[okantex]

Hi
I used 12v 45Ah car battery for test.
also used 1100miccrohenry D=5cm small coil,ırf840 ,vu meter, and 0.5W 8ohm speaker.
rest are same with kt315 's list.

first I hear sound like door creak .it continues something like 10 seconds .then stops .and when I put metal (it was iron) infront of coil ,I got no sound.

when I repeat process.I mean close and open detector .same thing happens again.

where is the problem
I connected 555's 2. & 6. pins.

And on vu meter there is + and - inputs.where must I connect them.which one is jp1 (+ or -)

[unhapyy4]

hı... I made a delta pulse but ı have a problem. my delta pulse sound always beeeep ı dont know where is my mistake? please help me. how can ı work it:?

[mosha]

I need to make two coils for Delta Pulse, 2*2 M & 50cm.

any help please for the wire gauge and number of turns.

thank you,

[1843]

I need to make two coils for Delta Pulse, 2*2 M & 50cm.

any help please for the wire gauge and number of turns.

thank you,

2x2m: 13turns 20AWG
50cm: 33turns 22-24AWG

For better coils you should ask ivconic!

Good luck

[mosha]

thank you very much

[Geo]

For 2x2m coil it is better to try 9 turns with wire 1.5...2.5mm

[Geo]

Hi all,
Can I use MC14538 instead of CD4538?

Yes . Yesterday i finished a Delta Pulse for a friend and it works perfect with MC14538 that shop sold to me.

[Max]

Yes . Yesterday i finished a Delta Pulse for a friend and it works perfect with MC14538 that shop sold to me.

Hi Geo,
nice to ear it works perfect ! It's really valuable machine... I know!
Of course it works too with mc14538... they are just Motorola kind of cd4538! (or ONSEMI version)
Also sometimes these are even more stable
Try also mc14066 and let me know... I've noticed really smooth operations with that stuff in sockets.
Buy with confidence.

Best regards,
Max

[1843]

For 2x2m coil it is better to try 9 turns with wire 1.5...2.5mm

Hi Geo,
With 1.5mm wire, the coil totally resistance(with cable) become 1ohm. So the MOSFET burns! DP doesn,t work with coils less than 2ohms.
Regards

[Geo]

Hi Geo,
With 1.5mm wire, the coil totally resistance(with cable) become 1ohm. So the MOSFET burns! DP doesn,t work with coils less than 2ohms.
Regards

Hi 1843. Total resistor must be at least 3...4 Ohm so you must connect in series a resistor 2...3 Ohm/1w. Large coil needs bigger current to create a larger magnetic field. For example Mikron says that Delta Pulse needs 110ma with disk coils and 180ma with square coil 1x1 m.
Regards

[Geo]

Hi Geo,
nice to ear it works perfect ! It's really valuable machine... I know!
Of course it works too with mc14538... they are just Motorola kind of cd4538! (or ONSEMI version)
Also sometimes these are even more stable
Try also mc14066 and let me know... I've noticed really smooth operations with that stuff in sockets.
Buy with confidence.

Best regards,
Max

Hi Max. I wrote this because before time an unregister guy asked if we can replace CD4538 with MC14538. If you look at datasheets you will see that at MC14538 there is at one input a smitt triger (if i remember ok) that there is n't at CD4538.
I have n't MC14066 to try it. Sorry but i stay at a small city with only one shop with electronics components.
My Regards

[Max]

Hi Max. I wrote this because before time an unregister guy asked if we can replace CD4538 with MC14538. If you look at datasheets you will see that at MC14538 there is at one input a smitt triger (if i remember ok) that there is n't at CD4538.
I have n't MC14066 to try it. Sorry but i stay at a small city with only one shop with electronics components.
My Regards

Hi Geo,
"there is at one input a smitt triger " yes there is at input A, right, of mc14538.
I think that's why it's somehow more reliable than standard cd4538... due to less sensitivity to jitter problems on this input.
Used also in other detectors and always they work really good.

Kind regards,
Max

[Geo]

I attach the very known schematic of Delta Pulse. I want from EE here to see the shematic and tell me about one question.
R20 is in series with a potentiometer 20K to regulate the gain (and the sensitivity of the detector). R20 is connecting to the inverter input of D5A. The gain of D5A(tl062) is R21/(R20+Rgain...potentiometer). So when the potentiometer is at zero resistance we have the maximun gain =R21/R20.
Yes...... BUT ......
Now i have 2 dtectors Delta Pulse that work fine and the maximum sensitivity (and max depth) is when the potentiometer is at full resistance (low gain).
WHY?????
I wait
Regards

[1843]

I attach the very known schematic of Delta Pulse. I want from EE here to see the shematic and tell me about one question.
R20 is in series with a potentiometer 20K to regulate the gain (and the sensitivity of the detector). R20 is connecting to the inverter input of D5A. The gain of D5A(tl062) is R21/(R20+Rgain...potentiometer). So when the potentiometer is at zero resistance we have the maximun gain =R21/R20.
Yes...... BUT ......
Now i have 2 dtectors Delta Pulse that work fine and the maximum sensitivity (and max depth) is when the potentiometer is at full resistance (low gain).
WHY?????
I wait
Regards

Hi Geo,

When you lower the Gain pot, you have reduced the noise!!
So you have increased the S/N ratio.

Have fun,
1843

[Qiaozhi]

I attach the very known schematic of Delta Pulse. I want from EE here to see the shematic and tell me about one question.
R20 is in series with a potentiometer 20K to regulate the gain (and the sensitivity of the detector). R20 is connecting to the inverter input of D5A. The gain of D5A(tl062) is R21/(R20+Rgain...potentiometer). So when the potentiometer is at zero resistance we have the maximun gain =R21/R20.
Yes...... BUT ......
Now i have 2 dtectors Delta Pulse that work fine and the maximum sensitivity (and max depth) is when the potentiometer is at full resistance (low gain).
WHY?????
I wait
Regards

Perhaps you have the potentiometer connected incorrectly. Try connecting R20 to the other end of the pot.

[Max]

I attach the very known schematic of Delta Pulse. I want from EE here to see the shematic and tell me about one question.
R20 is in series with a potentiometer 20K to regulate the gain (and the sensitivity of the detector). R20 is connecting to the inverter input of D5A. The gain of D5A(tl062) is R21/(R20+Rgain...potentiometer). So when the potentiometer is at zero resistance we have the maximun gain =R21/R20.
Yes...... BUT ......
Now i have 2 dtectors Delta Pulse that work fine and the maximum sensitivity (and max depth) is when the potentiometer is at full resistance (low gain).
WHY?????
I wait
Regards

Hi,
yes seems strange... your are right about gain, zero res. at pot and you get maximum gain of d5a. But there is not just gain to consider.
As above indicated you must rely on S/N... so I think that lowering gain there mean increasing signal to noise ratio, thus sensitivity.
I think that increasing gain there would amplificate noise in a bigger amount than useful signal. If so...
You know that integration in next stages would mask you noise averaging it... so if increasing gain to maximum mean reducing S/N you'll get less sens cause a same amount of signal is masked out by bigger noise amount and then averaging mask you a part of useful signal that wouldn't be compromised at minimum gain.

Why this could happen ?
Impeadance matching between stages, frequency response alteration of d5a stage related to your operating frequency, noise due to components (Rgain add its own that is proportional to its "used" resistance)... and many others related... like crosstalks in the pcb.
So, it's difficault to find why, what the reason(s) is(are)... but effect you noticed would for sure be related to S/N degradation with increasing gain.
Finding it would mean, maybe, reducing its impact on S/N degradation... with some mod (like I did e.g. in bandido adding gnd plane) thus gaining some depth with increased gain of d5a.
I know from other experiences that most of the times this behaviour depends by PCB design and assembling of boards.

Best regards,
Max