proscan

[dot]

hi all
i made the proscan and corected the mistake made by paulo, it works, but can hardly detect.
can any one help?
thanks

[Rado]

Re: proscan

Hi,

I have build the Proscan 2 months ago. The tranzistor T4 is wrong wired, ( Carlos told me that, thank you Carlos). Base of T4 goes to R17, collector to R20 and emitor to 7th pin on U5. Another source of insenzivity: use of piezo instead of headphones or capacitor in series with headphones (just like in Sandbanks ). I dont know why (maybe someone tell me...). With piezo or cap. in series the 2p. coin is registered at 3-4 cm, without at app. 16-17 cm.

[dot]

Re: proscan

hi rado
i tried the t4 but somthing wiered is happening!
it works in revers ie the kliks are stoping whene detect a metal but stil poor sesetivity.
the capasitor work nice.
thanks
and ill love some more help...

[Rado]

Re: proscan

You must tune it to the other side of maximum with pot. P2.

[Carlos]

Re: proscan

Hello all, I write in spanish and traslate with de systran in english, sorry. Hay mucha confusion con respecto a todos los detectores PI, es muy importante el lugar en la onda de decaimiento donde hay que hacer la lectura. Los valores de las resistencias y los condensadores para el tiempo de retardo y de muestra son aproximados ya que hay que ver en el osciloscopio como es la curva y por consiguiente, adelantar o retrazar los tiempos, yo uso preset para hacer el ajuste final.

Carlos


Hello all,
There is much confusion with respect to all detectors PI, is very important the place in the decay wave where there is to take the reading. The values of the resistance and the condensers for the time of delay and sample they are approximated since there is to see in the oscilloscope as it is the curve and therefore, advance or to delay the times, I use preset to make the adjustment final.


Carlos