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How does a pull up resistor affect the input pin?
With a pull-up resistor, the input pin will read a high state when the button is not pressed. In other words, a small amount of current is flowing between VCC and the input pin (not to ground), thus the input pin reads close to VCC.
Why does my ups beep when the power goes out?
When the power goes out and it switches over to battery power, your UPS will beep loudly every 30 seconds. This is your cue to save your work and do a Shutdown right away. It can also be disconcerting if this happens in the middle of the night.
Can a ups be plugged into an extension cord?
It may sound counterintuitive, but don’t plug the UPS into an extension cord, a surge suppressor, or a surge suppressor into the UPS (or a surge suppressor into another surge suppressor).
Can a ups Charger be plugged into a ups?
Also, after turning off your computer, in an emergency you could plug your cell phone charger into a battery outlet of your UPS to charge up your phone, but I wouldn’t leave your charger plugged into the UPS all the time.
How does a pull up resistor work in a logic gate?
With a pull-up resistor connected, the output still works in the same way as a normal logic gate in that when the output transistor is OFF (open), the output is HIGH, and when the transistor is ON (closed), the output is LOW. Thus the transistor turns ON to pull the output to a LOW level.
How does the pull up resistor work on a VCC?
When the button is pressed, the input pin is pulled low. The value of resistor R1 controls how much current you want to flow from VCC, through the button, and then to ground. When the button is not pressed, the input pin is pulled high. The value of the pull-up resistor controls the voltage on the input pin.
Why do you need a pull up resistor on SparkFun?
When the button is not pressed, the input pin is pulled high. The value of the pull-up resistor controls the voltage on the input pin. For condition 1, you don’t want the resistor’s value too low. The lower the resistance, the more power will be used when the button is hit.
Why does no current flow through the input pin?
If you hear that no current flows through the input pin, that’s because in most cases micro-Amp leakage currents can be effectively ignored in circuit design. The voltage after the pull up resistor will be a reduced voltage, however not by much. A voltage divider is still formed between the MCU input resistance and the pull up resistor.