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Does a reed switch need a resistor?
You just have to program them to set them into pull up mode. Then you connect one side of the switch to the pin and the other side to ground. No external resistors needed.
Why do reed switches fail?
Reed switches or relays eventually fail in one of three ways . They do not open when they should (usually called “sticking”), they fail to close when they should (“missing”), or their static contact resistance gradually drifts up to an unacceptable level .
What activates a reed switch?
Although a reed switch can be activated by placing it inside an electrical coil, many reed switches and reed sensors are used for proximity sensing and are activated by a magnet. As the magnet is brought into the proximity of the reed sensor/switch, the device activates.
Are reed switches polarity sensitive?
Form B type Normally closed and Form E type Latching reed contacts are polarity sensitive.
How accurate is a reed switch?
Magnetic reed switch technology has been a proven technology for more than 50 years to dependably and safely sense a wide range of liquids and positioning. The internal switches are hermetically sealed and capable of switching 1/8″ accuracy and 1/32″ repeatability for standard vertical switches.
Where can I buy a reed switch circuit?
Reed switches can be obtained cheaply from a number of online sellers, such as ebay or Tayda electronics ( Tayda Electronics- Reed Switches ). Reed switches are normally rated to handle a maximum amount of current and voltage.
What happens when a reed switch is connected to a cable?
In case a reed switch is connected to a load by cable, over a long distance, static capacitance caused by the cable will affect the contact characteristic of the reed switch.
How does a reed switch hook up to a SparkFun?
Reed switches are magnetically-actuated electrical switches (not magically-actuated, though it seems that way sometimes). When the body of the switch is exposed to a magnetic field — like a magnet or even a strong electrical current — two ferrous materials inside pull together, the connection closes, and current can flow.
Can a reed switch be closed without a magnet?
There are normally open reed switches and normally closed reed switches. Normally open reed switches are those that are open circuit when placed into a circuit without a magnet in its vicinity. Without a magnet near the switch, the circuit will be open, so that no current flows through the circuit.