# Can a reed switch use a wheatstone bridge/potential divider?

• Daniel2244
In summary, the principle of operation of a reed switch involves the use of a magnet to open and close the switch. It is not commonly used in a wheatstone bridge or potential divider arrangement, which are typically used for resistance devices such as strain gauges and LDRs. However, an LDR can be used in a potential divider arrangement to control the switching of a transistor and LED based on the amount of light it receives. In a wheatstone bridge circuit, an LDR can be used in place of a resistor to produce a varying voltage based on changes in light. If a long, thin wire is wound around the reed switch and connected to the wheatstone bridge, it could potentially control the galvanometer. Additionally,
Daniel2244

## Homework Statement

Describe the principle of operation of reed switch and LDR using wheatstone bridge and potential divider arrangement

I can't find any website that says a reed switch uses a wheatstone bridge or potential divider arrangement. The only find I have found it that that a magnet if used to close and open the switch. When a magnet is moved towards the open reed switch it causes the reed pins to move together completeing the circuit. And when a magnet is applied to a closed reed switch it causes the reed pins to repel causing them to open breaking the circuit.
Because they work using a magnet I wouldn't think they would be used in a wheatstone bridge and potential divider arrangement because they are manly used for resistance devices. For example, strain gauge and LDR.

## The Attempt at a Solution

I understand how a LDR is used in a potential divider arrangement:
When the resistance of the LDR is small (When light intensity on LDR is very high),there is a small voltage drop across the LDR; this means that the output voltage (Vout) from the voltage divider is small and the transistor is switched off.
In the dark the large resistance of the LDR takes a large share of the voltage supply so Vout is large and the transistor and LED both switch on.

And in a Wheatstone bridge circuit:
In a Wheatstone bridge circuit an a resistor is replaced (normally labelled Rx) with a LDR. As light changes it causes the resistance of the LDR to change which produces a voltage across the bridge of the circuit

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It would help if we knew the grade or context of the question.

What would happen if you wound a long thin wire around the reed switch, then connected that coil across the wheatstone bridge in place of the galvanometer?

What could you do if the reed switch controlled a light source that illuminated an LDR in different positions in the bridge circuit?

## 1. Can a reed switch be used in a wheatstone bridge?

Yes, a reed switch can be used in a wheatstone bridge circuit. However, it is important to ensure that the switch is placed in a position where it can be easily activated by the desired magnetic field.

## 2. How does a reed switch function in a wheatstone bridge?

A reed switch is a type of electromechanical switch that consists of two metal contacts sealed within a glass tube. When a magnetic field is applied, the contacts are pulled together, completing the circuit. In a wheatstone bridge, the reed switch is used as a variable resistor to balance the bridge and measure the resistance of the unknown component.

## 3. Can a potential divider circuit be used with a reed switch?

Yes, a potential divider circuit can be used with a reed switch. The reed switch can be used as one of the resistors in the circuit, and the voltage across the switch can be measured to determine if it has been activated.

## 4. What are the advantages of using a reed switch in a wheatstone bridge/potential divider circuit?

Reed switches are compact, low cost, and have a long lifespan, making them a popular choice for use in electronic circuits. They also have a low contact resistance and a high switching speed, making them ideal for use in wheatstone bridge and potential divider circuits.

## 5. Are there any limitations to using a reed switch in a wheatstone bridge/potential divider circuit?

One limitation of using a reed switch in a wheatstone bridge or potential divider circuit is that it can only be activated by a magnetic field. If the switch needs to be activated by something other than a magnet, another type of switch may be more suitable. Additionally, reed switches can be sensitive to shock and vibration, so they may not be suitable for use in certain environments.

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