testing of componets

[Ray]

I am sure most of you test your componets prior to using them. Well I did not. I was having problems with the Hammerhead and could not get the preamp to work right. So as a last resort I started checking the wiring from pin to pin and found I had a changing 3 to 6 meg ohms on the output back to the input. This is supposed to be a 1 meg feedback resitor. Turns out the whole batch of 1 meg resistors was bad. Lesson learned.
Ray

[Gene L.]

Re: testing of componets/Hammerhead

To save me time which option would you suggest for better discrimination on aluminum foil or pull tabs . Inverting pre-amp option looks better for notch rejection ? Well whatever I figure, it will be a great detector and Fun project.. Thank-You Gene L.

[Ray]

Re: testing of componets/Hammerhead

Gene I am still relearning all I forgot about electronics so you will have to ask someone else. Mine picks up aluminum very nicely. along with iron. I detect a small screw driver about 15 inches away. Right now I am getting ready to put componets on the board that I received from Carl yesterday and start testing it.
Ray

[Carl-NC]

Re: testing of componets/Hammerhead

The new PCBs are set up only for the inverting opamp configuration. PI's do not discriminate tabs, or much of anything else.

- Carl

[Gene L.]

Re: testing of componets/Hammerhead

Inverting opamp it is. Thanks Carl.. Gene L.