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How to use op-amp with NTC driving LED lights?
Op-Amp Comparator with NTC driving LED Lights This comparator circuit consists of a NTC sensor, and operational amplifier (op-amp), which drives red and green LEDs, lighting them according to the sensor input. In this example circuit, we utilise a negative temperature coefficient (NTC) thermistor, which is a sensor device that senses temperature.
How does an op-amp work on a led?
Q1: large N-channel MOSFET. U2: Just a voltage regulator to power the op-amp and give constant current to R1+Pot1. R1 and Pot 1 (current set resistors) values set the maximum current of the LEDs by changing the voltage across Pot 1. This sets the maxiumum voltage across R2, the current sense resistor.
Which is comparator circuit drives red and green LEDs?
This comparator circuit consists of a NTC sensor, and operational amplifier (op-amp), which drives red and green LEDs, lighting them according to the sensor input.
Why does the op-amp swing at saturation?
It does this by subtracting one input value (Y) from the other input value (X) because we are using the inverting and non-inverting inputs of the op-amp. Since there is no feedback loop, the operational amplifier will operate at saturation, and therefore the output voltages will swing just below +9 V or just above 0 V.
When to use the op-amp comparator for LEDs?
The comparator therefore compares the voltages at points X and Y and it can tell if the voltage at point X is greater than Y or less than Y and the output voltage lights the LEDs accordingly. When the voltage at X is greater than Y the op-amp output is closer to ~9 V and the red LED should light.
What is the op-amp of a red LED?
When the voltage at X is greater than Y the op-amp output is closer to ~9 V and the red LED should light. When the voltage at X is equal to or less than Y, the the op-amp output is closer to ~0 V, and consequently the green LED should light.
How is the led sequencer using 4017 decade counter?
This LED Sequencer using 4017 decade counter circuit is very easy to build, and shows a sequence of lights (LEDs) that lights up one by one. How the LED Sequencer using 4017 works?