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DC motor

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Geno03245

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MikeMl

got your addition today, thanks

switch for demonstration model will be push button > for website design prototype, switch will be relay controlled by wall-mount intermatic timer

9V DC transformer stopped working >> ?? it was old >> or the ends grounded out

new transformer fresh out of box >. all spectrum P/N: AD-121AN
input 110V AC > output 12V DC 1000mA (1Amp) 2.1mm, center positive

I am studying your schematic quick as possible > some questions will be answered by your addition

Question 1: the 2 wires on DC transformers are marked > which of 2 wires is negative? I assume wire marked with long dashes is negative.
Question 2: on the schematic, ground goes to positive, correct?
 

MikeMl

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MikeMl
...
Question 1: the 2 wires on DC transformers are marked > which of 2 wires is negative? I assume wire marked with long dashes is negative.
Question 2: on the schematic, ground goes to positive, correct?

1. Do you have a Multimeter? Put it in DC VOLTS mode; that will answer the question unambiguously. If the meter reads positive, the Red lead is connected to the positive lead of the power supply. Marking on wires is mixed bag. The marked wire could be positive.

2. No. The negative goes to the ground symbol. The positive goes everywhere it says "9V". Now, I worry about your new 12V power supply. If it is unregulated, then lightly loaded (i.e. all the time the motor in not running) that supply is likely have an output of about 18V, which is TOO HIGH for the logic and 555s in my circuit!!! You need to check the unloaded voltage with a voltmeter before connecting it to my circuit...

AS far I can determine, your new 12V 1A supply is unregulated. This type of supply may or may not have a filter capacitor inside it. I fear that even if it does, the capacitor will be too small to filter the output while the motor is drawing ~0.25A. A regulated power supply may be needed.
 
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