Delta Pulse

[dbanner]

Or better yet, do online crash course in electronics, then when you have aquired sufficient knowlege, you can climb mount everest.

[dbanner]

That should be zeitnitz soundcard oscilloscope, connect via soundcard input using basic buffer circuit you can find online. Warning, DO NOT CONNECT ACROSS COIL, only measure output of 556. you can also build a soundcard interface which offers dc restoration and overvoltage protection.

[dbanner]

you have multimeter which has freq. range, yes? Or use pc based oscilloscope like zenitz, connected via soundcard input. This software also displays frequency of signal being measured.

[6666]

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

to test the output of the 556, you can use a simple speaker and series capacitor to listen to any clicks made by the 556 this is about as low tech as you can go,
you could also use a small audio amp to listen to the clicks, I would suggest you google
Electronics for Beginners

[kt315]

set o-scope probe on outputs of 556 and look pulse width and frequency.

[abdennour]

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

[dbanner]

You CAN measure output of 556 with o-scope.

[abdennour]

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

[bernte_one]

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

[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.

[abdennour]

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

[kt315]

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

[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]

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]

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