ABSTRACT

  When you apply 5 volts to voltage test terminal then LED was turn on. But If you apply 25 volts to voltage test terminal then LED was turn off. Form results happen because of circuit have compare by operational op-amp. If you want to test by 25 volt or more than 12 volts, then LED was turn off because transistor was not work and current are not into load because relay was work then common contact with NO port. But you want to test by 5 volts or more than 12 volts, then LED was turn on because transistor was work and current are into load because relay was not work then common contact with NC port.

MEMBER

Mr. Natsakorn Liangsorn