Delta Pulse

[abdennour]

a little but I understand quickly , Thank you .

[kt315]

coil data

[abdennour]

Thank you I needed that , I also have a problem there is no frequency at the output coil ???

[kt315]

is there the delta pulse on the coil? thats your question.

[dbanner]

How do you know there is no output frequency? Do you have oscilloscope? Stop mucking around here and give us more details on your rig.

[abdennour]

https://www.google.dz/imgres?imgurl=...act=mrc&uact=8

[kt315]

you can not measure output voltage or frequency on a coil by a tester or an o-scope.
the value is huge. we call it HIGH VOLTAGE - HV.
with PULSE WIDTH 150us there will be 120-150V p-p.
with PULSE WIDTH 500us there will be 1200-1500V p-p. (oh i remember a mosfet cuts the pulse on a top like
a zener... so just you can grasp me)

[abdennour]

I did not know that , so why when the coil is not connected there is a noise in the speaker, and when I connect it there is no noise even when turning all the potentiometer ???

[kt315]

look what you have to hear on TURN ON. https://www.youtube.com/watch?v=3yZuOn4bc6o

[abdennour]

I have this noise but without coil, and when I connect the coil nothing ?

[kt315]

coil is low value resistor itself you CLOSE the input of operational amplifier (FRONT END) on power line, ie
on the input there is NO SIGNAL, NOTHING, CLOSE CIRCIUT, NO NOISE.
if you OPEN the input disconnecting the coil you get the noise just preamp amplifies own noise.
plus there are still other opamps in the circuit. every one will amplify the noise.

[bernte_one]

i am interested in one sniffer xr71 pcb, where can i get one?

[abdennour]

when I remove the coil and I connect a voltmeter i found 7.5 V ,

[dbanner]

You CAN measure output of 556 with o-scope.

[abdennour]

i do not have an o-scope, I will try to find a friend who has one , how to test the 556 ?