An AC mains solid state relay or SSR is a device which is used for switching heavy AC loads at mains level, through isolated minimal DC voltage triggers, without incorporating mechanical moving contacts.
在本帖里,我们学习如何构建一个简单的马在s operated solid state relay or an SSR circuit using a Triac, BJTs, a zero crossing opto coupler.
固态SSR优于机械继电器
机械类型的继电器在需要高度光滑，非常迅速和干净的开关的应用中效率低下。
建议的SSR电路可以在家中构建，并用于需要真正复杂的负载处理的地方。
A mains 220 V solid state relay circuit with in built zero crossing detector is described in this article.
该电路非常易于理解和构建，但提供了有用的功能，例如清洁开关，没有RF干扰，并且能够处理最多500瓦的负载。我们已经学到了很多有关继电器及其功能的知识。
我们知道，这些设备用于通过外部隔离的触点切换重型电荷，这是响应从电子电路输出中收到的小电脉冲。
通常，触发输入位于继电器线圈电压的附近，可能为6、12或24 V dc，而继电器接触的负载和电流大多在AC电势的水平上。
基本上，继电器之所以有用，是因为它们能够切换与触点的重型连接，而无需使危险的潜力与易受攻击的电子电路接触。
However the advantages are accompanied by a few critical drawbacks which cannot be ignored. Since the contacts involve mechanical operations, sometimes are quite inept with sophisticated circuits which require highly accurate, quick and efficient switching.
Mechanical relays also have the bad reputation of generating RF interference and noise during switching which also results in its contacts degradation with time.
For a MOSFET based SSR please参考此帖子
Using SCR or Triac for Making SSR
Triacs and SCRs are thought to be good replacements in places where the above relays prove inefficient, however these too may involve RF interference generation problems while operating.
Also SCRs and Triacs when integrated directly to electronic circuits require the circuit’s ground line to be connected with its cathode, which means the circuit section is now no longer isolated from the lethal AC voltages from the device – a serious drawback as far as safety to the user is concerned.
However a triac can be very efficiently implemented if the above discussed couple of drawbacks are completely taken care of. Therefore the two things which must be removed with triacs, if they were to be efficiently replaced for relays are, RF interference while changeover, and the entry of the dangerous mains into the circuit.
固态继电器的设计完全使用上述规格，从而消除了RF推理，并且还使两个阶段完全与其他阶段保持了。
商业SSR可能非常昂贵，如果出现任何问题，则无法维修。但是，您将全部制作固态中继并将其用于所需的应用程序可能就是“医生订购的”。由于可以使用离散的电子组件构建它，因此可以完全可以修复，可修改并为您提供有关系统内部操作的清晰想法。
在这里，我们将研究简单的220V固态继电器的制造。
How it Works
As discussed in the above section, in the proposed SSR or solid state relay circuit design the RF interference is checked by forcing the triac to switch only around the zero mark of the AC sine phase and the use of an opto coupler ensures that the input is kept well away from the AC mains potentials present with the triac circuit.
让我们尝试了解电路的功能：
如图所示，光耦合器成为触发电路和开关电路之间的门户。输入触发器应用于光电的LED，该Opo启动并制造了光电传感器。
The voltage from the photo-transistor passes across the collector to the emitter and finally reaches the triac’s gate to operate it.
上述操作非常普通，通常与所有三元人的触发器相关。但是，这可能不足以消除RF噪声。
The section comprising the three transistors and some resistors are especially introduced with the view of checking the RF generation, by ensuring that the triac conducts only in the vicinity of the zero thresholds of the AC sine waveform.
当将交流电源应用于电路上时，光晶晶体管的收集器可用，并如上所述进行导电，但是在连接到T1底座的电阻器的连接处的电压是如此调整，以至于立即进行操作，以至于立即进行操作。AC波形上升后，高于7伏标记。长期以来，波形保持在此级别之上，保持T1打开。
这是基于光晶晶体管的收集器电压，抑制了TRIAC的导电，但是当电压达到7伏且接近零时，晶体管停止导电以允许TRIAC切换。
The process is repeated during the negative half cycle when T2, T3 conducts in response to voltages above minus 7 volts again making sute that the triac fires only when the phase potential nears zero, effectively eliminating the induction of zero crossing RF interferences.
基于TRIAC的固态继电器电路的电路图
零件清单
- R1 = 120 K，
- R2 = 680K,
- R3 = 1 K,
- R4 = 330 K,
- R5 = 1 M,
- R6 = 100欧姆1 W，
- C1 = 220 UF / 25 V，
- C2 = 474 / 400 V Metalized Polyester
- C3 = 0.22uF/400V PPC
- Z1 = 30 volts, 1 W,
- T1, T2 = BC547B,
- T3 = BC557B,
- TR1 = BT 36,
- OP1 = MCT2E或类似。
PCB布局
Using SCR Opto-Coupler 4N40
Today with the advent of modern opto-couplers, making a high grade solid state relay (SSR) has really become easy. The 4N40 is one of these devices which uses a photo SCR for the required isolated triggering of an AC load.
This opto-coupler can be simply configured for creating a highly reliable and effective SSR circuit. This circuit can be used for triggering a 220V load through a thoroughly isolated 5V logic control, as shown below:
SSR使用MOC3020光耦合器IC和TRIAC
ICS MOC3040或MOC3041与正常opto-coupler其中典型的光晶体管由光横幅（100 mA/400增值税25°C）取代。该IC的主要特征是，它实际上允许在电路中使用所有形式的硅控制整流器（SCR）和TRIACS，通常不可能使用phototransistor基于光耦合器。根据继电器要运行的负载类型，可以确定制造220V操作的固态继电器的TRIAC类型。
Considering that the SSR load is resistive, the triac TIC 226D/400 V can be used satisfactorily. In case, an inductive load is specified for the load, a 630 V triac may be required, for example, a type TIC 226M, can be necessary. Remember the working voltage of capacitor C1 should match the specs of the triac used.
The input side resistor R1 can be determined depending on the level of the input voltage, V在。可以使用以下公式评估其价值：
R1 = 1000（V在- 1.3)/IOC。
在此等式v中在will be in volts, R1 is in ohms, and IOC将在MA中，这表明通过MOC光耦合器中的LED电流。
If we consider the LED side input of the opto coupler to be V在= 12 V, and the current IOC= 30 mA（这是MOC 3040光耦合器的标准规格），R1的效果值将等于356欧姆，我们可以将其圆将其圆成到实际可行的330欧姆。
In the MOC 3041 the current specification Ioc of the LED is simply 15 mA, which means that, practically it may be possible to allow the R1 limiting resistance value to be around 680 Ohms. The maximum current this 220V solid state relay can handle is approximately 8 Amps, for higher power you can change the triac accordingly
Image courtesy:远方
Hi Swagatam
I am looking for an SSR which can handle 100A 12V load, input voltage 6 – 12V.
I assume the above circuit is suitable for AC main loads.
HI ABU-HAFSS，如果根据指定的载荷电流对所示的TRIAC进行了充分的额定值，则肯定可以适用于相同的。
Hi Swagatam
I have read somewhere that DC SSR should not have zero crossing detector and should have an SCR instead of traic.
HI ABU-HAFSS，上面的电路设计用于控制主电位的交流负载，因此零交叉对抑制噪声和干扰是有利的。
这就是我要问的，您能为我提供一些DC SSR的设计，而无需零越过探测器，能够在12V时处理100A。
…if possible i'll try to design and publish soon.
你好，先生
感谢您的帖子
我可以知道C3的价值吗？
谢谢
Hi Ngo, You can use 0.22uF 400V for C3
你好，
如何修改该电路以将其与120V 60Hz一起使用？
Does it need to be modified?
谢谢。
No, it does not require any specific modifications for 120V. This is unrelated, I think there should have been a diode 1N4007 in between R3, and C2 line, cathode towards R3…And aslo a 33 ohm 1 watt in series with the input AC line to safeguard the zener!
是否可以使用SCR或其他固态设备控制220VAC 5000至10000瓦加热器？
Yes, definitely possible!
Swagatam, can you help me get started, components, circuits etc.
谢谢
Jim, you can try the following concept:
//m.addme-blog.com/how-to-make-25-amp-1500-watts-heater/
All capacitors are 400V rated and the resistors are 1/4 watt 5%
先生，该电路适合在用于传递主电源和发电机之间的负载的ATS系统上更换接触器？约50安培。
不，该电路不能用作转换继电器。
Swagatam先生你好,
希望你好好安全。正在与MOC3021和BT136进行固态继电器。并计划与PIR传感器集成。我的查询是如何在传感器模式之间切换它，并始终“轻上”模式。
Previously I made the circuit with electromagnetic relay and directly connected the light to phase line with a two way home switch. So I can toggle between sensor and always ON.
Now connecting the TRIAC with the light, I guess I cannot connect light directly to the switch and it may damage the triac. Kindly help.
谢谢Mr.Sriram, You can simply connect a switch between the (+) and OUT pins of the PIR to bypass the positive directly to the MOC input, and this will enable always Light ON or PIR mode operation.
是否有任何简单的固态直流继电器电路，从6伏到14伏。
注意 - 目的是闪烁LED，负载将为60瓦 @ 12.8伏
Use a BJT or MOSFET with the output of any opto coupler, that will fulfill your requirement.
你好。
What can I use instead of sc 1460?
You can use any standard triac.
Can I use “Circuit Diagram of Triac based Solid State Relay Circuit” with a 2HP water pump?
是的，您可以使用它！
谢谢for all this information , I was wondering if could use one MOC3040 to drive two Triac to control two AC separate lines?
可以将TRIAC+MOC3040用于DC/AC负载控制吗？
您是否建议使用保险丝进行TRIAC保护？
不客气！是的，使用TRIAC和MOC OptoCOPLER可以使用所有这些功能。保险丝始终是所有交流电路的推荐设备，因此必须包括在内。
HI Mr. s. thank you for your kindness to answer me . Actually I interest to electronics . I work on it for years. I found many pieces of old scr in my friend workshop. they are so big I think 150 amps. I imagine they used them for controlling kids electric cars. now I like to use them as a ssr controler. I need some help . first of all I know I should parallel them to use as a TIC , but I do not know if it works instead , If it works you think I can use it in your above diagram. ???? . can you help me. thanks.
嗨,你们s you can use your SCR in the above shown circuits, but being an SCR and not a triac, it will only work with 50% of the AC cycles….
你好 。如果我以相反的方式平行两个SCR，我有很多，我可以将其用作TRIAC吗？。如何计算电压和Miliampers同时发射两个？？？。可能吗 ？我的SCR是
BSTL3590 . large , 250 amps and 1.2 kv. can yo help me ?
thanks for your help.
嗨，我不确定，但是您可以尝试一下。您可以将两个门连接起来，并将每个SCR门带有1K电阻器。之后，您可以尝试使用直流信号切换电阻的公共端并检查响应。
THIS CIRCUIT IS INTERESTING BUT PLEASE WHERE THE NC AND NO CONTACTS OF THE RELAY. CAN WE USE THIS FOR AUTOMATIC VOLTAGE STABILIZER
There’s no NC contact, only NO contact across the load terminals. You can use it for stabilizer application also.