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The root cause of the hysteresis (aka "snap-on" effect) in simple triac/diac dimmers is the capacitor not being discharged by the diac in the previous half-cycle and entering the subsequent half-cycle with the opposite voltage across it. Consider just the positive case where the capacitor is negatively charged from the previous half cycle. The negative ...


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Parallel connection of 2-wire dimmer switches is fine. Note that the first one to switch on will control the brightness. i.e., The one with the brightest setting will win. This is due to the way the triacs in the dimmers switch on at a certain point in the mains cycle. Figure 1. Triac dimmer control. Note that the earlier in the mains cycle that the power ...


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The device inside the MOC3023 is an opto-triac, not a diac. A diac is triggered by voltage across it, whereas the opto-triac is triggered by light from the LED. The maximum current in the opto-triac should not exceed 50mA (except very briefly) since above that the triac is guaranteed to turn in in the relevant quadrants (I/III). I am not familiar with ...


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With the circuit as it is, the load does always consume power. This is not a good thing, it means that the load needs a minimum wattage to stay 'off'. However, it's not too bad a thing. It's made even less bad by most triac light controls having a real switch in series so they can be turned off. The triac control is intended to replace the switch in the wall,...


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It is a very standard dimmer circuit. When used properly (with the right kind of load) it is very efficient as it quickly switches on and off. It is mainly usable for resistive loads which means oldfashioned lighbulbs. It is less suitable or even unsuitable for most LED lights, fluorescent lamps, electric motors. Electric motors can be dimmed but you need a ...


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What you're missing is you have two circuits. Yes, the current flows from live, through the triac, through the motor, then down the white wire to neutral. However, current also flows from live, through the capacitor (remember, it's AC we're dealing with here), through the resistors, the switch+resistor pair, and down the white wire to neutral. Some also ...


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Devices such as the MOC3041 will only turn on as the supply goes through zero - this is desirable for controlling loads such as heaters or motors as it can reduce the interference they cause and avoid getting partial cycles. The load will be either fully on or fully off. Any PWM that is desired can only be performed at a very slow rate - this is acceptable ...


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Why is it that in every triac analog dimming circuit I find that the triac triggering circuit is fed through the load and not straight from the mains? In most countries there is no neutral available in the wall switchbox where the dimmer is mounted. Arranging the circuit to find a neutral path through the load avoids having to rewire the switchboxes with ...


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To make a light dimmer you have to use a non-zero crossing triac driver. For example, the MOC3051/52. These are sometimes called "Random Phase Triac Drivers". You typically also need a zero crossing detector. To control the brightness you vary the time delay between each zero crossing and triggering the triac, from close to zero (for close to full power) ...


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The component is almost certainly a metal oxide varister. It is designed to absorb voltage surges by shorting them out but it is not designed to take sustained overvoltage. Connecting a MOV chosen for a 120V only application to a 240V supply will almost certainly destroy it. As to replacing it unfortunately googling the part number printed on the device ...


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Here are some thoughts. As Pieter said in his answer, this would be easy for DC: you would use a diode to prevent current to flow back to the grid. But for AC, you can design something that behaves like the diode in DC: simulate this circuit – Schematic created using CircuitLab You would connect your inverter and your home equipment to the “OUT” ...


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Disclaimer: I am just an amateur, get professional advice. If you have two DC sources it would be easy, you just add a one way (diode) and power/current can only flow in one direction. You might be able to simulate this by feeding grid into UPS(double conversion AC->DC->AC) and then having your grid-tied inverter connected to the output of the UPS. Thus ...


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It's going to be almost impossible without a deep knowledge of how that particular inverter detects the incoming mains supply. Block the mains, and the inverter will shut down, as it's designed to do. Leave the mains connected, and it will start exporting, as it's designed to do. It's not clear why you'd want to do this anyway.


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You are almost there. The only missing thing is synchronization with ac votage. This is how you can achieve it: Now the capacitor charging will be in sync with applied ac voltage. This will give you triac firing in 1st and 3rd quadrant.


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There are multiple ways to tackle the problem of providing 3 pre-set light levels. Three R/C/Diac networks and one Triac simulate this circuit – Schematic created using CircuitLab Or even simpler still.... Just three potentiometers, one DIAC and one Triac simulate this circuit You could fairly easily modify a single dimmer to satisfy either of ...


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ZCS and PWM cannot be used together. You can soft start with ZCS or soft start with increasing PWM duty cycle then adjust final duty cycle to get average voltage. The reason for ZCS control is that light bulbs with tungsten have a cold resistance about 10% of hot and thus draw 10x the current if started at mid phase or peak voltage. Dimmer triacs have a ...


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There are many diacs (I don't believe it should be capitalized) available on the market, most currently sold are variations on the DB3 part number. Older numbers included the ST2 originated by General Electric. A diac is a bidirectional switch that breaks over at a controlled voltage in each direction. It does not behave like two zener diodes- it has a ...


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The circuit will quite likely work without the DIAC - i.e., short out where the diac should be until you can get one - but may be a bit "twitchy". Without the DIAC the TRIAC will turn on when the trigger voltage gets high enough. The problem is that this is not very well defined and will vary depending which quadrant the triac is operating in and, probably, ...


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Off course the dimmed lamp will use less power than the full lamp .OK you could do your circuit from the internet which must be good.You will probably find the dual time constant dimmer more stable at low light levels .If you live close to a street transformer you may blow the dimmer when the bulb blows which may defeat the proposed savings .I have seen ...


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