开关

一般霍尔传感器的运行时间是5 µs, 干簧传感器是 100µs emr 可达10 ms。

霍尔传感器不能直接切换电压。干簧和emr 传感器可直接切换电压高达1000V。

霍尔传感器可供应微瓦信号，干簧和emr 传感器可直接切换高达100w。

仅干簧和emr 传感器可直接切换。

干簧传感器可调整磁滞从35%到95%。霍尔和emr 传感器有固定磁滞。

是的。仅霍尔传感器需要斩波电路和驱动。

仅霍尔传感器对输入极性敏感。

仅霍尔传感器正常运行时需要外加电流。

Yes, they only supply a small milli-volt signal in the presence of a magnetic field. The signal needs to be amplified and then fed into a switching circuit.

A voltage is produced on a semiconductor material when in the presence of a magnetic field.  The voltage is proportional to the strength of the magnetic field.

Best to use a small copper plated reed switch in an application where the carry current is about 3 amps RF.  Greater than 3 amps you should use a large copper plated reed switch.  The RF will be riding on the outside ‘skin’ of the switch.

霍尔传感器的绝缘强度小于10V，emr典型的是250 V，和干簧传感器的绝缘强度可以高达5000V。

霍尔传感器输出电容通常是100pf，干簧传感器只有0.2pf，和EMRS通常是20pf。

霍尔传感器的释放时间通常为5μs，干簧管传感器为20μs和 emr  5毫秒。

霍尔传感器不能切换任何输出电流，干簧管传感器和emr 通常可以直接切换高达2 A。

通常霍尔传感器超过200欧姆，干簧和EMR传感器通常50毫欧。

是的。输出极性仅对霍尔传感器的正常运行起关键作用。

使用Standex Electronics KSK-1A85干簧管系列。

使用ORD228，ORD211铱，或ORD311。

For a sensor use the ORD228 with iridium or the ORD2210 for a relay.

小型机电继电器不适合低电压和低电流切换。机电继电器需要强大的电压和/或电流来打破任何薄膜堆积。正是这种薄膜堆积不允许极低的电压和电流通过触点。干簧开关显然是最佳的解决方案。使用镀钌触点或铱触点是这些低电负载的最佳材料。

Most reed switch blades are made of nickel/iron that has a relatively high resistance to current flow when compared to copper and silver.  Most of the time it is not a problem. However, when the reed switch is asked to pass high current, whether DC or AC the contacts will heat up.  The heat can become so high that the curie point is reached > 700°C.  At this point, the nickel/iron loses it ferromagnetic properties.  Therefore, the relay coil or magnet holding the contacts together will no longer hold the contacts open due to the excess heat.  To solve this problem plating the entire reed switch with 50 to 100 µm of copper will improve the conductivity so much that the problem will disappear.

切换和击穿电压达到250V及以上最佳使用真空干簧开关。在电流不太高的情况下，ORD2210V可以有效地达到4000V。电压高于4000V时,建议使用密封干簧开关。

Miniature reed switches less than 20 mm (0.80 inches) glass length can effectively break up to 250 Volts.  This depends on the pull-in AT (mT) used.  The higher the better.  Reed switches less than 10 mm will shrink this value to around 150 volts.  Minimizing the current flow at the time of opening will improve this value.

Reed switches whether they are used in sensors or relays all will be asked to switch some load.  Generally there are two aspects to this load.

1. Its steady state load
2. Is the actual switching taking place during the first 50 nanoseconds.  This is also called the signature of the load.

This signature takes into consideration not only the steady state load but also any transient voltages or current that may be present during the first 50 nanoseconds.  These transients may be from stray capacitance, inductance in the line and/or common mode voltages.  From a reed switch designer standpoint, the signature is all there is.  The most important time during the switching of a load is that first 50 nanoseconds.  That is when all the damage to the contacts with occur if you are switching the contacts ‘hot’.  If a customer is having a problem with early failures, this is the first place to look.  Equally important and not to be overlooked is what voltage and current is actually being broken when the contacts open.  Any healthy voltage and/or current present will chew up the contacts rapidly leading to sticking reed contacts.

There are several key factors:

1. You need to have an idea of the required load.  What voltage and current is being switched at the time of closure for the first 50 nanoseconds?
2. How many operations will be required during the life of the product?
3. What are the size requirements?  How much room is needed?
4. How will the product be mounted? Surface mount, thru hole, etc.
5. For long life and low levels, use a ruthenium or an iridium sputtered/plated switch.
6. For switching applications from 50 Volts to 200 volts use the Philips/Coto/Comus sputtered ruthenium switch.
7. For switching currents 25 ma to 1 amp, the KOFU thickly plated rhodium is good along with our KSK-1A35.
8. For higher voltages above 200 volts  up to 4000 volts at relatively low current use the  OKI ORD2210V.
9. For voltages above 1000 volts up to 10,000 volts with higher currents use the Hermetic vacuum switches.  This represents a start.  One could write a book on this subject.  Best to find out the exact customer load and run a life test with a few or several reed switches to make the final determination.

1C干簧管是指单极双掷干簧开关。  It is hermetically sealed with 3 leads:

1. A common lead
2. A normally open lead
3. A normally closed lead

When operated the common contact will swing from the normally closed contact to the normally open contact. This is caused by the magnetic field produced by a coil or the magnetic field from a magnet.  When the magnetic field is removed the common contact will revert back and come to rest on the normally closed contact.

The reed switch once it is sealed is subjected to a partial annealing process.  This partial annealing process leaves a stress on the glass to metal seal (hermetic seal) and is actually done to make the seal stronger.

When metal is subjected to a very high temperature bath, that process is called annealing.  The temperature is slowly increased to a max temperature where it is stabilized for a period of time, and then the temperature is slowly reduced back to room temperature.  This process will leave the metal in its softest state.  For a reed switch this is very important because this point is also where the nickel/iron leads have near zero magnetic retentivity.  This means when the reed switch contacts are subjected to a magnetic field and then the magnetic field is removed, there will be no residual magnetism on the leads.

Most metals do not like to be connected to different metals.  A few metals like other metals.  The most popular ones are gold and copper.  These two metals when brought together with other metals will diffuse into that other metal.  These metals are like the glue that holds two different metals together. This process gives rise to multiple levels of plated or sputtered metals.

密封有三种类型：

1. 玻璃与玻璃密封
2. 玻璃与金属密封
3. 金属与金属密封

这些密封件将密封内部与外部环境完全隔绝，零缝隙度，即使在分子水平也不存在任何泄漏。

Sputtering is a new process where the material is embedded in the soft nickel/iron layer, where plating is simply electroplated on the soft metal.  The problem is that if the plating is not perfect, flaking can occur between the very hard outer plated level and the soft inner metal.

没有。对干簧管没有净效应，一旦磁场使干簧管触点饱和，它就不再有任何影响。

A magnet and reed switch can be turned into a temperature sensor by using a magnet that has a certain curie temperature for the temperature you want to sense.  When that curie temperature is reached the magnet loses its magnetic properties whereby the reed switch contacts open.  When the temperature drops below the curie temperature, the reed contacts will close.

Currie Temperature.  The reed contacts become so hot that they reach the currie temperature of the nickel/iron material.  At the currie temperature the materials lose their ferromeagnetic properties.

The nickel and iron are relatively soft.  When you switch voltage and current  across the contacts some of the metal will melt and transfer to the other reed contact.  When you switch often enough, a sufficient amount of  metal will transfer and sticking will occur. Plating and/or sputtering a harder metal like rhodium or ruthenium will dramatically reduce the amount metal that is transferred and therefore directly increasing the life time or number of cycles before sticking will occur.

磁场仅对铁磁体金属产生影响。镍和铁均属于铁磁体。52% 镍 至关重要，因为它的热膨胀系数正好与玻璃体的膨胀率完全匹配。