可以使用TRIAC构建有效的固态单极双掷或SPDT开关，以替换机械SPDT。
该帖子使用OptoCOPOPLER和几个TRIAC详细介绍了简单的固态TRIAC SPDT继电器电路，可用作有效替代机械继电器。这个想法是由“ Cypherbuster”要求的。
介绍
在其他帖子之一中，我们学会了如何制作DPDT SSR using mosfets, however this design could be used only for high current DC loads, and not with AC loads at the mains level.
在本文中，我们将看到一个简单的电源如何操作solid-state relaycan be made using triacs and an optocoupler.
任何继电器的工作均专门旨在在外部隔离的低功率触发器的帮助下单独和交替操作两个不同的高功率负载。
在一个conventional mechanical type of rely this is done by toggling the loads across its N/O and N/C contacts in response to the activation applied across its coil.
但是，机械继电器有自己的缺点，例如较高的磨损程度，较低的寿命，由于触点上的火花而引起的RF扰动的产生，最重要的是延迟的切换响应，这可能至关重要像UPS这样的系统.
电路操作
In our triac SPDT relay circuit the same function is executed through the switching of two triacs via two BJT stages and an isolating optocoupler which ensures that the changeover operation for this relay has no drawbacks as mentioned above.
参考图，左侧TRIAC表示N/O触点，而右侧TRIAC像N/C接触一样运行。
电路原理图
While the optocoupler is in the non-triggered mode, the BC547 directly associated with the opto goes into the triggered mode, which keeps the second BC547 switched OFF. This situation enables the right side triac to remain switched ON, and the other triac is held switched OFF.
在这种情况下任何负载与对吗t triac becomes operational and stays switched ON.
Now as soon as a trigger is applied to the opto coupler, it switches ON, and in turn switches OFF the connected BC547.
这种情况打开了第二个BC547，因此右侧TRIAC被关闭，以确保左侧TRIAC现在打开。
上面的条件立即切换第二个负载并关闭较早的负载，并在隔离的外部DC触发器的帮助下有效地实现了负载所需的替代切换。
The two LED connected with the bases of the two BJTs indicate which load is in the activated state at any moment while the triac SPDT relay circuit is being operated.
Adding an attached power supply and Delay Effect
The above design could be further enhanced and made fully independent of an external DC power source by upgrading it with its own transformerless power supply, as shown below:
You will find the following changes in this upgraded diagram:
Addition of a 1K at the base of the right BC547 to ensure correct triggering of the left side triac
在三进一步的大门上添加R/C网络，以确保在任何给定的实例或转换期间，两个TRIAC永远不会在一起。二极管可以为1N4148，电阻可以为22k或33k，电容器可以约为100UF/25V。
该图中似乎还缺少一件事，这是12V Zener二极管和0.33UF电容器之间的有限电阻（约22欧姆），这对于保护Zener Diode可能很重要。电源开关期间的电容器。
警告：上面显示的电路不是从电源交流输入供应中隔离的，因此在切换状态下接触的情况极为危险。
车道菲什伯恩说
您是否需要某种电容器延迟，以便两者都不同时使用？甚至这么轻微吗？
伟大的电路 - ！
Swagatam说
感谢Lane指出的内容，我已经更新了文章底部的延迟功能的设计，您可以检查一下。
瓦卡说
兄弟，
Can you provide circuit for three phase Solid State Contactor.
谢谢。
Swagatam说
当然，兄弟，我很快就会使用重型Triac进行。
puneetSwarup说
嗨，斯瓦加塔姆，
您的邮件中还有一个查询，请建议。
谢谢
Swagatam说
answered!!
puneetSwarup说
Hello Swagatam,
I have sent the modified diagram on mail, as you had suggested. Please have a look and let me know your valuable feedback.
谢谢，
puneet
Swagatam说
你好puneet，我回答了。
Swagatam说
yes that's possible.
Sharoj Al Hasan说
先生，我找不到晶体管BC517先生，我可以使用BC547替换该晶体管吗？
Swagatam说
you can use two BC547 and connect them in Darlington form for getting the equivalent of BC517
Swagatam说
It is my pleasure Devendra ji. thank you and God bless you!
Cypherbuster说
Thanks a Ton!
Another thought: A relay does not require a continuous power supply, i.e, even under no power conditions, there's a connected terminal and an open terminal.
是否可以消除外部5-12伏特并将其变为继电器的确切状态版本？
Swagatam说
I am glad you liked it…please check out the last diagram I have updated it as per your suggestion.