Op Amp Schmitt trigger



The Op Amp comparators sometimes works well under some conditions but not always. If there is a slow wave form or some noise on it, sometimes the output switch back and forth many times. So for stable operation, Op Amp comparator can be designed as a Schmitt trigger.
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Power status LED


Two LEDs indicate the power on and off status of bread board power . So it helps to confirm whether the positive and negative rails of the bread board are getting power. Green LED lights at power on and turns off after 3 seconds. Red LED turns on at power off and turns off after 3 seconds. Let us see the circuit

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LED in AC


It is easy to light an LED by directly connected to 220 volt AC. It can be indicator in AC devices or Bed lamp if White LED is used. If used as a Bed lamp, the circuit can be enclosed in a plug  with LED projecting out. Caution : The circuit is directly connected to high voltage that can give a fatal shock if handled … Continue reading LED in AC