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My circuit as created by Geda


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Your schematic is a negative image that is too small with colored lines and text on a black background. Nothing can be seen.


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Thank you for fixing the schematic so that it can clearly be seen.
Does the circuit work properly?


You are most welcome. It worked fine on the breadboard.

After soldering, it beeps all the time.

The soldering was very difficult and stressful, but I learned a ton.

I used a 4x magnifier. Could have used a 10x.

I only had stranded wire to use for the connections.

I have copper tinned wire but was afraid it might short out the circuit if the wires got pressed down.

I am waiting for some Kester 44 solder. I used the wider Radio Shack solder.

I used to wonder why people use such narrow solder.

I wonder no more. :)

I am wondering if my knock off solder iron is really setting the temp correctly.

It was set to around 350 C. When I switched to a very narrow tip, about 1/3 of it melted off. ?

My regular tip does not melt off.

Later, after I have fully recovered, I will recheck my work.


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My Weller soldering iron is about 50 years old and has its tip temperature always at the correct temperature with no adjustment. Cheap soldering irons use a simple lamp dimmer to adjust the power, not the temperature. Mine does not sit there getting hotter and hotter and hotter melting itself and incinerating the important rosin in solder. If I try to solder something large then it does not cool down like a cheap soldering iron. Its tips last for years when used every day.


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The circuit cannot work as shown. You have the Threshold input tied directly to Vcc.

What is S1?


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