A simple electronic ceiling fan regulator circuit using a triac and a diac is a common type of circuit which is used to control the speed of a ceiling fan.
This circuit basically works using phase control principle, in which the voltage supplied to the fan motor is varied by controlling the firing angle of the triac.
A diac is used to trigger the triac at a certain voltage level as determined by the setting of the potentiometer knob.
Let's break down the circuit step by step and explain the working of each component:
Triac is normally employed to work like a regulator device, which enables the adjustment of fan speed through phase-triggered power control principles.
This involves switching ON and switching OFF the triac once during each half-cycle of the mains power supply. The proportion of time the triac remains switched ON or OFF determines the average AC power supplied to the fan.
In order to eliminate radio frequency interference (RFI) issues caused by the rapid triggering of the triac, it is essential to incorporate a straightforward LC filter into the fan's power supply line.
There are a couple of basic methods widely used to achieve variable phase-delay triggering.
One method involves utilizing a diac in conjunction with an RC phase delay network, while another method employs a line-synchronized variable delay UJT trigger.
Simplest Fan Regulator Circuit
Below is an illustration demonstrating the practical setup of a diac-triggered simplest fan regulator circuit. In this fundamental configuration, R1-RV1-C1 form the variable phase delay components.
One drawback of this simple design is the presence of significant control hysteresis or backlash.
For instance, if the fan speed is reduced by increasing the RV1 value to 470k, it won't start again until RV1 is reduced to approximately 400k, and it will then operate at a relatively high speed level.
This "backlash" or the hysteresis issue is attributed to the diac partially discharging C1 each time the triac triggers.
Eliminating the Hysteresis Effect
To mitigate the "backlash" or the hysteresis effect in the aforementioned circuit, one can incorporate a 47 Ohm resistor in series with the diac, reducing its impact on discharging C1.
An even more effective solution is to employ the gate slaving circuit, as depicted in the following circuit
In this configuration, the diac is triggered from C2, which effectively replicates the phase delay voltage of C1. Additionally, R2 safeguards C1 against discharge when the diac triggers.
Hum Free Regulation by Eliminating RF Noise
In the above triac-based fan regulator circuits, the coil L1 and capacitor (C2, C3) combination acts as an RF filter to decrease electromagnetic interference (EMI) and create a hum free power supply to the fan.
This ensures smoother and more regulated functioning of the fan's speed control circuit.
This LC network aids in the reduction of electrical noise and disturbances, which can otherwise affect the functioning of the fan and other nearby electronic equipment such as radios, amplifiers, TV sets etc.
L1 Construction
Regarding the construction of L1, the core consists of a 30 mm long segment of a 9.6 mm diameter ferrite aerial rod.
Wind two layers of 20 turns in close proximity, focusing on the central 15 mm section of the core, using 0.63 mm diameter (22 B&S) enameled wire. Finish by covering it with two layers of plastic insulation tape.
Practical Design Without Filter Coil and Capacitor
If the RF humming noise generation is not an issue to you, then you can ignore the filter coil and the capacitor elements and build the fan regulator circuit without these components as shown in the following diagram.
Step 1: Connecting the Resistor
Connect the 1/4 watt resistor in series with the potentiometer.
Step 2: Connecting the Diac
Connect one terminal of the diac to the junction of the potentiometer's middle terminal and one end terminal.
Connect the other terminal of the diac to one of the terminals of the triac (usually the gate terminal, denoted as "G"). This connection allows the diac to trigger the triac at a certain voltage level.
Step 3: Connecting the Triac
Connect the main terminals of the triac (A1 and A2) in series with the fan motor.
MT1 is connected to the phase/hot AC supply, and MT2 is connected to the load (fan motor). The gate terminal (G) of the triac is connected to the diac.
Step 4: Connecting the Potentiometer
Connect the variable terminal of the potentiometer to the common junction of the diac and the triac gate.
Connect one end of the potentiometer to the circuit's ground (usually the neutral line). Connect the other end of the potentiometer to the AC mains supply line (phase).
Step 5: Connecting the Diac control Capacitors
Connect the two capacitors C1 and C2 associated the diac, as indicated in the circuit diagram.
Step 6: Optional Filter Capacitor
To reduce noise and interference, we can connect a capacitor in parallel with the fan motor. The value of the capacitor depends on the specific application.
Components needed:
- 1K 1/4 watt 5% CFR = 1no
- 6.8K 1/4 watt 5% CFR = 1no
- 220K Potentiometer (variable resistor) = 1no
- 0.1uF / 400V Capacitor PPC = 2nos
- Triac (e.g., BT136) = 1no
- Diac (e.g., DB3) = 1no
Working Principle of Each Component
Potentiometer: The potentiometer works like a voltage divider. By adjusting the potentiometer, we change the voltage applied to the diac, which in turn controls the firing angle of the triac.
Diac: The diac is a bidirectional trigger device which conducts as soon as a certain voltage threshold is reached. It allows the triac to trigger and start conducting in both halves of the AC cycle.
Triac: The triac is a bidirectional semiconductor switch. When triggered by the diac, it allows current to flow through the fan motor.
By changing the firing angle of the triac, we control the amount of voltage and power delivered to the fan motor, thus controlling its speed.
Capacitors: The capacitor associated with the diac is responsible for introducing a phase shift. This phase shift determines when the diac is allowed to trigger during each AC half-cycle.
This phase shift in turn controls the firing angle of the triac, allowing us to control the power and thus the speed of the fan motor.
By adjusting the potentiometer, we are able to change the triggering point of the diac through the capacitors C1 and C2. This changes the phase angle of the triac conduction.
This phase control mechanism effectively controls the speed of the fan motor.
Caution
Remember that this circuit works with dangerous high-voltage AC power. Extreme precautions, insulation, and expertise are necessary while handling this circuit.
We strongly recommend consulting an experienced electrician or engineer while constructing and testing the above fan regulator circuit.
Understanding Triac Phase Control
Triac phase control using phase chopping is a method employed in the above circuit for regulating the speed of a ceiling fan.
In this approach, the triac is triggered to conduct only during a portion of each AC half-cycle, allowing us to control the effective voltage and power delivered to the fan motor. This, in turn, regulates the speed of the fan.
Let's dive into the details of how triac phase control using phase chopping works in the context of your ceiling fan regulator circuit:
AC Voltage and Triac Behavior:
AC voltage alternates between positive and negative half-cycles, with a frequency of 50 or 60 Hz.
A triac can be triggered to conduct in either direction when a certain gate voltage is applied to it. Once triggered, it remains conducting until the current drops below a certain threshold (holding current).
Basic Working:
The main aim of the triac phase chopping method is to control the firing angle at which the triac is triggered to conduct.
By triggering the triac at different points within each half-cycle, we are able to control the portion of the AC waveform that is delivered to the load (fan motor).
Phase Control and Speed Regulation:
During the periods the triac conducts early in a half-cycle (near the beginning of the AC waveform), it delivers more voltage and power to the load. This increases the fan motor speed.
Conversely, when the triac conducts later in the half-cycle (closer to the peak of the waveform), less voltage and power are delivered, resulting in a slower fan motor speed.
Potentiometer Adjustment:
The potentiometer in the circuit serves as a variable resistor, allowing you to adjust the triggering point of the diac.
As you adjust the potentiometer, you change the gate triggering angle of the triac, which controls when the triac starts conducting in each AC half-cycle.
Diac and Triggering:
The diac works like a triggering device for the triac. The diac fires and starts conducting only once a certain voltage threshold is reached.
Each time the diac conducts, it triggers the gate of the triac, allowing it to conduct and control the flow of current to the load (fan motor).
Variable Speed Control:
By adjusting the potentiometer, it is possible to change the phase angle at which the triac is triggered to conduct.
This causes a continuous adjustment of the fan motor speed due to the control of the effective voltage and power supplied to the motor.
Another 220V Ceiling Fan Regulator circuit Diagram and prototype images Submitted by a Dedicated user of this blog
The choke is built using 5 meters of 30 SWG super enameled copper wire over a 1/2 inch diameter and 1 inch long ferrite core.
5 Step Fan Regulator Circuit
The above mentioned basic fan regulator circuit can also be adapted to achieve a 5 step control of the fan speed.
This adaptation involves substituting the potentiometer with a 5 way rotary switch connected to four fixed resistors, as depicted below:
The resistors might follow an increasing sequence such as: 220K, 150K, 120K, and 68K. Alternatively, you could experiment with different combinations within the range of 22K to 220K to find the most suitable configuration.
Parts List
- C1 = 0.1u/400V (optional)
- C2, C3 = 0.022/250V,
- R1 = 15K,
- R2 = 330K,
- R3 = 33K,
- R4 = 100 Ohms,
- The four stepped resistor can be as explained above.
- Diac = DB3,
- Triac = BT136
- L1 = 40uH (optional)
Conclusion
In summary, triac phase control which uses phase chopping is a technique which allows a smooth and continuous speed regulation of the fan motor.
This is basically implemented by varying the phase angle at which the triac conducts within each AC half-cycle. The potentiometer and the diac are used to control the triac gate triggering angle.
This in turn effectively controls the amount of power delivered to the fan motor, and thus, the speed of the ceiling fan.
This method offers a simple and efficient way for the user to adjust the fan's speed according to the required preferences.
Questions & Answers
I work mostly in digital, allegedly one of the problems with the Triac controls of AC motors is that it generates heat and Hum – you address hum above.
But I have wondered why cant an AC motor like a Ceiling Fan be speed controlled by varying the frequency. VFD’s are used to control speed on Industrial motors.
Is it possible to do a very simple low power (100w or less) pure sine inverter using SPWM and something like an Hbridge without a transformer to control a ceiling fan speed in a reasonable sized package ?
Bascially AC-DC and then Back to AC with about a 100hz frequency range. An ESP32 ought to be able to easily generate SPWM in those frequency ranges – or even a real low voltage sine wave that is amplified by an HBridge
Hi, thanks for your interesting question. That is definitely possible, however using any other complex method other than the traditional triac phase chopping method appears to be an extreme overkill. Because the triac phase chopping concept is highly efficient in terms of power dissipation, except the RF generation, which can be easily controlled by LC low pass filter circuit. The heat generated by the triac is quite nominal, and no matter which concept you apply, this much dissipation will be always there, and cannot be avoided.
That said, i have actually already developed a simpler PWM variant for AC fan speed control, which you can read in the following article:
https://www.homemade-circuits.com/pwm-controlled-fan-dimmer-switch-circuit/
Thanks for your response. My background is embedded software – I am fairly competent with digital circuits – particularly at the sub mhz level that is typical of most embedded hardware.
I am not a complete idiot with analog circuitry – I have electronics from college physics – 40+ years ago, and my work with embedded systems periodically exposes me to analog circuits – but I am far from fluent.
I have read conflicting information on using Triacs/PWM for controling the speed of AC motors, Varying from – Works great to, that is a big mistake. I am also gathering that the type of motor matters – and again while I have basic understanding – I sort of understand how a shaded pole motor works, I am not competent to determine which of two contradictory opinions is correct.
I am heavily involved in home automation – mostly as a hobbiest – from software through to designing and building my own hardware – again mostly digital.
But certain things like speed control on fans are stretching my abilities.
I am an embedded software developer by profession – home control is a related hobby. Frankly – though again I have other people dealing with the analog portions of my commercial projects – they are more sophisticated and complex than my HA projects.
I looked at all the projects you linked.
https://www.homemade-circuits.com/control-lights-fan-using-tv-remote-full-circuit-diagram/
In this circuit cant I replace everything through to the 4027 jk flip flop with a GPIO from an embedded CPU ? And how are you syncing with Zero Crossing ?
Thanks for explaining your background. I understand your point…..Triac-based speed control works quite well with many ordinary ceiling fans using capacitor-run induction motors. It controls the speed by chopping each AC half-cycle and reducing the effective voltage supplied to the motor. However, the results depend on the motor type. Some motors may produce more noise, heating or vibration with this method. The RF interference can be reduced using a properly designed EMI filter, and the triac heat dissipation is generally quite low compared to the power handled by the motor. You can certainly use a microcontroller for zero-crossing detection and precise triac triggering. However, for a simple fan regulator, a conventional circuit is usually cheaper and simpler. An MCU becomes useful when you need additional features like home automation, remote control or programmable speed settings.
And yes you can replace the complete IR signal-processing section, including the CD4001 gates, monostable and CD4027 flip-flop, with a microcontroller. The TSOP1836 output can be connected directly to a GPIO input. The microcontroller can detect the IR pulse, apply a suitable delay or lockout to prevent repeated triggering, and toggle its output ON or OFF. Regarding zero-crossing, this circuit uses the MOC3041 optotriac driver, which has an internal zero-crossing detector. It triggers the main BT139 triac near the AC zero-crossing point, so no separate zero-crossing input to the microcontroller is required for simple ON/OFF switching. However if you want to control the AC phase angle or implement precise timing based on the AC waveform, you will need a separate zero-crossing detector and suitable control logic. The MOC3041 is not suitable for phase-angle control.
And Yes, you can replace the IR receiver and CD4001/CD4027 logic with a microcontroller. Connect the TSOP1836 output to a GPIO and handle IR decoding and ON/OFF toggling in software. The MOC3041 has an internal zero-crossing detector, so no separate detector is needed for simple ON/OFF switching. However, phase-angle control requires a separate zero-crossing detector and a random-phase optotriac such as the MOC3021.
I beleive you have answered my question even if I did not express it clearly.
For most small motors shaded pole motors and smaller induction motors, Triac/PWM control of speed is viable – the artifacts that result on the Triac side – EMI/heat etc can be handled with good circuit design, and in most cases issues like heat and vibration at the motor will be small.
I would still love to see a simple mini single phase VFD if that ever piques you.
Regardless, thank you for your site, for your explanations of your circuits, and for your helpful replies to my questions.
Sure, here’s a simple VFD design without using microcontrollers. Of course it is just a crude version, which can be further refined for more efficient results:
https://www.homemade-circuits.com/single-phase-variable-frequency-drive/
Thanks very much for your kind words, I am always happy to reply to my readers, and I truly enjoy it, and it also helps me to learn new things.
Please keep up the good work, and please do not hesitate to comment whenever you have anything new to share with this world.
Thanks for your reply. And thanks for all the wonderful circuits on our website and your explanations of them – for someone with my background they are very helpful.
For most of us when we have a nail – a hammer is what we are good at. I am very good at embedded software. Today and ESP32C3 is less than $3 and has 1000 times more power than the first desktop I owned. People do not hire me – unless there is some embedded processor. Even my own projects start with an embedded processor. I not only asume the existance of a processor in my projects, but assume bluetooth and wifi and more horsepower than I will ever be able to use. I recently constructed a refridgerator sensor board – because the doors in our fridges were being left open and the coils were freezing up.
It is so trivial today to add sensors – a DS1820 Temp probe for the internal temp, a bmp280 for the outside, a reed switch for the door, and a buzzer and LED for alarms and a web server on board so that the whole thing could operate completely locally AND still be connected to the home control system and Alexa or Google or … And still that $3 ESP32 is mostly loafing.
I hve decades of experience in this – but we have made all of this so easy that lots of people with far less experience can do what I do. There are people on the web with a fraction of my embedded experience doing amazing things. Further the recent AI explosion has made it so that nearly anyone can manage the same things.
But things become difficult for me – and probably myriads of others as we enter the analog world.
I was less concerned about the heating, Hum and EMI of the triac then overheating the motor. But maybe I was misunderstanding other web sources.
I understand basically how a PWM and a Triac modify an AC wave and very basically how that effects lights, motors, leds …. But understanding basically is not the same as knowing how that effects efficiency, over heating, life expectancy, …
“However, the results depend on the motor type. Some motors may produce more noise, heating or vibration with this method.”
This is the type of things that are outside the scope of my knowledge and experience.
“The RF interference can be reduced using a properly designed EMI filter”
I do not even begin to know how to do that – that is what websites like yours help with.
“However, for a simple fan regulator, a conventional circuit is usually cheaper and simpler.”
Embedded processors are ridiculously cheap today. If I was prepared to go back to assembler and abandoned wifi and blue tooth. there are fairly capable processors for $0.25 that can often replace significant other circuitry
Besides – if I have a nail to drive – my hammer is an MCU – while I have preferences ANY MCU gets me into my world.
Even inside my commercial work I am constantly telling clients not to value engineer projects before they are working – and that in most instances probably never. I have been hired multiple times to get DDR working with some processor because the client cut the memory in half from the reference design to save money. Unless a client is making millions of something, the cost in engineering will take years of saving $1/product to repay, Further almost every time a client has reduced the resources, later – often before production they have increased them again because new potential uses drove greater resource needs.
Regardless my projects and my clients are not for GE or GM, and not made in the millions, they are for myself or for smaller makers and made in the thousands or rarely 10000s value engineering in that domain is rarely a wise choice.
I am not knocking value engineering. It just is counter productive in my world.
“And yes you can replace the complete IR signal-processing section, including the CD4001 gates, monostable and CD4027 flip-flop, with a microcontroller. ”
While I asked I pretty much understood that – that section is digital and within my experience.
“The TSOP1836 output can be connected directly to a GPIO input.”
Just finished project like that a few months ago – including deciphering an IR remote and then duplicating its functionality. There are myriads of IR controlled appliances that can be controlled by adding a $1 IR LED to an MCU.
The big problem there is that IR is completely open loop.
Thanks for your kind words and detailed explanation. Yes, I agree, automation using sophisticated chips has become a child’s play nowadays, especially because nowadays coding can be done in seconds using any only AI platform. Earlier coding used to be the monopoly of the expert coders, but nowadays the analog guys can also do the coding and interface complex automation systems with analog hardware and build complex systems quickly.
That said, still some analog circuits do not need any sophisticated upgrades, for example our electronic ceiling fan dimmers which are perfectly suited to capacitor-start type ceiling fan motors and they can literally fit inside an ON/OFF switch socket and can be built at less than a $. I have even used BLDC ceiling fans and have found them to be bad in terms longevity and price and there speed seemed to become slower overtime, and also once it goes bad, it is almost impossible to repair them. Capacitor start motors are still the best when it comes to longer life and cooling and repairing.
Phase chopping dimmers are efficient since they work like analog pwm, by delaying and chopping the AC waveform into smaller sections, so that lower speeds are implemented by keeping the fan turned off for longer durations and vide versa.
Thanks for your observations – as I have noted, I am a software guy working really close to the hardware. I can look at some analog circuits and know what they do – atleast in general terms and I can figure out many things especially in simpler circuits but I do not know and do not have your experience to be able to make much of the judgement and analysis that you make. Your observations on BLDC’s in interesting. I get annoyed by the Name Brush Less DC motor – they are not DC – they are AC motors they are AC frequency speed controlled with the same AC frequency being fed to usually 3 coils in the motor 120 degrees apart in phase. But they are commonly used with DC power sources and ESC’s converting that DC to the requirements of the motor. I am surprised that they are seeing a higher failure rate – They are arguably mechanically simpler than normal AC induction motors. A ceiling fan motor and a BLDC are different in only two ways – the winding of the coils and the presence of a usually rare earth magnet in the BLDC motor.
Regardless, thank you very much for your observations.
You are absolutely correct!…thanks for your detailed insights. It is much appreciated.
I was part of a project at a major US Semiconductor manufacturer – should be pretty easy to guess working to put a Risc-v RV32 running 2Ghz with 2G or DDR on a single chip of memory silicon. This was supposed to be an ESP32 killer – it was supposed to be under $1/chip and run Linux – though I had input into the rest of the design porting Linux to it was my end. I was a consultant and my direct supervisor left to pursue other interests, and I fell off the project or the project died or … Regardless I have not seen it appear.
Espressif now has ESP32’s using a Risc-V – but not with enough Ram to run real linux.
But the target for this project was to expand the number of software developers who could do embedded programming from the few percent of all software engineers to pretty much anyone who could develop a linux app.
As Economist Julian Simon noted 30+ years ago “the ultimate resource” and the only truly limited resources is the human brain.
Most human attributes – like intelligence and domain skill distribute on a Bell curve and there are only a small fraction of people at the tail of the curve fro any given attribute.
We boost what we can produce and therefore standard of living when we make those 1 or more std dev back from the tails capable of doing what those at the tails can. When we can do that we massively increase what can be accomplished. The Project above exposed me to alot of knowledge about Silicon – that does not make me a chip designer, just better able to understand what is involved. Regardless one thing I knew before and was reinforced then is even though we are hitting the limits of physics with Silicon, we still have not been able to use a tiny fraction of the capabilities of silicon 40 years ago. I mostly work with embedded systems – I will always take more horsepower, but what is really needed is the means for less skilled people to write robust working code. Decades ago I put powerful software into 512 bytes of Eprom in 8 bit systems. Today I do “embedded work” on systems thousands of times more powerful than my first desktop that costs a bit more than $2,
I can write a bare metal APP for an stm32 – but more and more I find myself coding in what is essentially markup langauges that allow me to do fairly sophisticated IOT apps in 100+ lines of code that requires very little understanding of the underlying hardware.
There are people doing work similar to what I do that are just hobbiest home owners trying to automate their home – and succeeding, and that is without using AI.
While there will always be things we want to do – like decrypt the communications of foreign adversaries in real time, that require hardware better than we currently have, the reality is we have not utilized 1% of the capabilities of silicon technology from the 80’s it is capable people – not hardware that we lack. Or more accurately we need software and hardware – not way out at the bleeding edge, but that is capable enough that people 1 or 2 std dev back from the tails can do productive things. That increases what we can produce exponentially.
Thanks for sharing such a great perspective…. That RISC-V project sounds really interesting. If a sub-dollar chip with full Linux capability had come out back then, it would have completely changed the embedded world.
What you said about Julian Simon’s quote and reducing the entry barrier is so true. When we move away from complex low-level coding and rely on simple abstractions, it lets normal developers and even hobbyists build great things without needing years of hardware experience.
In the end whether it is done through smart chips, high-level languages, or simple tools, making technology easy for more people to use is what actually brings progress.
many of your circuits are interesting, but more and more things are being controlled by home control not switches and Pots.
I would like to see more circuits adaptable to control by an ESP32.
Yes, I have tried to address them in a few of my earlier articles, through the following simpler ideas.
https://www.homemade-circuits.com/control-lights-fan-using-tv-remote-full-circuit-diagram/
https://www.homemade-circuits.com/simple-remote-controlled-fan-regulator/
https://www.homemade-circuits.com/simple-220v-ac-push-button-fan-regulator-circuit/
In purchased fan regulator of both pritam and anchor is giving canch canch sound at low speed to 70 % speed in havels fan . But crompton fan is not giving such sound. what should I do?
The easiest solution is to replace the inductor with bigger inductor having higher number of turns. When you use a bigger inductor, it absorbs the sharp voltage spikes more efficiently and reduce these noises.
The Pritam and Anchor regulators and all similar regulators use Triac phase-chopping, which cuts the AC wave to lower the speed. The Havels fan motor laminations could be sensitive to these sharp voltage cuts, causing them to vibrate and hum, whereas the Crompton fan is built in a way that absorbs this noise.
Veľmi podrobne vysvetlená činnosť obvodu a všetkých súčiastok. Vďaka vám pane za túto prácu.
Thanks Majo, it’s my pleasure, glad you liked it…
Please advice 110volts regulator circuit for celling fan
I think the above circuits will work with 110V also, you will just need to use a pot with lower resistance value…maybe a 100k pot.
Would you please explain more about using a resistor in series with DIAC, What value of resistor should I choose and why ?
Thanks in advance.
The value can be anything between 50 ohm and 100 ohm, to safeguard the diac from sudden high current spikes.
Bro if I remove 220k ohm potentiometer and place a 10k ohm potentiometer. what are the changes should i do in the circuit to make the circuit works.
Hello Guddu,
It is not possible to replace the 220k pot with 10k.
why is it that if I turn off the load on a certain adjustment of the setting of potentiometer , let’s say the potentiometer is of 470k and I turn off the load at 300k , then when I turn on the load the voltage is higher than what I have previously set during turning it of , why is it so .
Which circuit did you try? Please try the second design with two capacitors C1 and C2. Or you can try using a 220k pot and check the results.
Let me know how it goes.
I think it is the first one, the load here is a transformer , the transformer is operated with a triac such that it provides a variable voltage at the output, suppose I use the transformer at 13v then when I turn it off and again turn it on next time the output voltage is more than 14v but the thing is that both the times the input voltage are same that is 230v , is it the backlash phenomenon?
Yes, it could be a backlash problem.
I would suggest you to first verify the output results using an 220V incandescent bulb, and check whether the bulb glow is always the same or not when you turn it ON or off.
If you have problems try a 220k pot, or try the second circuit with two capacitors.
thank you so much for your reply , I had tried with the bulb and the bulb did not show any noticeable difference if I turn off and turn it on again , seems like only the transformer is affecting the system , is this behaviour normal ?
by the way I am using a normal fan regulator and I have just removed the triac bt136 and put there bta41 with a big heatsink , so now it can handle large loads ~40A , is is okay to use this type of modified circuit?
Thanks for updating the results.
If the bulb is getting affected, that means the dimmer circuit has no problems, and there’s no backlash. You can further confirm this by turning the pot to minimum…if the bulb filament shows some glow even at the minimum level, would indicate a correctly configured circuit.
To check the transformer behavior you can put a 100 watt incandescent lamp in series with 220V inpput and check whether the lamp glow changes or not with subsequent ON/OFF switching.
According to me a transformer behavior should be normal just like the bulb, because i have confirmed the results using transformer and for me it worked without any issues.
Yes, BTA41 should also work fine… for the diac please use a DB-3 diac.
thank you for your reply , yes I am using a db3 diac , the whole circuit is same just the triacs are exchanged , by the way I am using a inverter transformer that is used to charge the battery , since if I connect the transformer directly to main power supply , it will produce 18 volt at the output and I only require 12 to 13 volt maximum , so I have to use a dimmer at the input of the transformer to lower the output voltage , so only the output voltage is getting affected if I turn off and turn it on again without touching the potentiometer knob , I will check with a series bulb 100 watt and report you the results , again thanks a lot for clarifying my doubts . it help me positively .
No problem, let’s see what happens when a bulb is connected in series…all the best to you.