I have to build a small alarm system. Voltage is 12V. The speaker is a small piezo sirene. SW2 should be the sensor. SW1 the activator. I want to have a control LED to see if sensor is open or closed.
If I mesure the voltage at the sirene, it is -10v. If I close switch1 I mesure 3V. If I close switch1 and switch2 I have 12V like expected.
I am a bit confused about the negative high voltage with all switches open.
If I mesure the voltage at the sirene, it is -10v. If I close switch1 I mesure 3V. If I close switch1 and switch2 I have 12V like expected.
I am a bit confused about the negative high voltage with all switches open.
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