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  #1  
Old 04-11-2014, 11:34 PM
fmnotes fmnotes is offline
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Default Negative pulse generator

Hello
knows someone, a circuit for a negative pulse generator?
eg with a 555! ????????
Thank you.
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  #2  
Old 04-12-2014, 04:58 AM
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Calculate R1,R2,C1 for duty cycle and out Frequency
You can use power supply <18V. Diodes are not critical
regards
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Old 04-12-2014, 09:43 AM
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opps sorry for a small false. Remove output elec capacitot 10 uF
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Old 04-12-2014, 01:16 PM
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Hi Andreas
The device can be tested pd & pdk & static & .... ?
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Old 04-12-2014, 05:23 PM
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Quote:
Originally Posted by ANDREAS View Post
opps sorry for a small false. Remove output elec capacitot 10 uF
Regards
Thank you my friend Andrea,
I have tried this circuit but I did not found
I have no negative output pulse.
Also I tried to add the little circuit output, and another signal generator but I did and there some negative pulse output.
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Old 04-12-2014, 08:18 PM
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Remove diode connection ground.
Few years ago, i build it, but i don't remember a small modification. My sense is diode.
I search tomorrow my library, maybe i find it or a better and simple schematic
best regards
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Old 04-12-2014, 08:19 PM
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Quote:
Originally Posted by reza vir View Post
Hi Andreas
The device can be tested pd & pdk & static & .... ?
No reza
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  #8  
Old 04-13-2014, 04:48 PM
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Hi dear friend Andreas
This circuit can detect metal ions?
Thanks and regards
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Old 04-13-2014, 04:49 PM
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Parts List:

R1 = 100M, 1/2W, 5%
R2 = 10K, 1/4W, 5%
R3 = 5K, potentiometer (see text)
C1 = 470pF, ceramic disc
Led1 = Led, red, 5mm
Q1,Q2 = PN2907 or NTE159M, try others like 2N2907
Q3 = PN2222 or NTE123AP, try others like 2N2222
M1 = 100mA, panel meter

Additional Parts and Materials:


Perfboard, plastic enclosure,
9-volt battery holder and connector,
wire, solder, hardware, etc.

R1 Note:

We couldn't find a 100-mega-ohm resistor.
We used (5) 20-mega-ohm resistors in SERIES to get 100-mega-ohms.
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  #10  
Old 04-13-2014, 05:06 PM
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Hi reza
Here is thread "Negative pulse generator" by fmnotes. If you need infos about other circuits-schematic is better open a new thread or go threads from your schematics
About your last schematic , my answer is no!
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  #11  
Old 04-13-2014, 05:16 PM
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Thanks Andreas
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  #12  
Old 04-14-2014, 05:41 PM
fmnotes fmnotes is offline
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someone else
not aware of any negative pulse circuit?

difficult question


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