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25 Threads found on Triac Power Supply
Hi I am using a triac to drive am AC contactor. the contactor coil is 1.25H & 385ohm The problem is that the snubber circuit burns when I turn on the supply "220V" What should be the R & C values and rating for the snubber circuit to drive such load? Best Regards Hossam
more details power supply ? relay , Opto triac wit zero detect DC power supply ? datashett on powersupply .. power (max Voltage , Watts or intensity) is PIC powered with another source ?
could you post the correct circuit? this one isn't isolated, as pin 2 from the 220-lamp connector (which goes to the triac) is connected to VSS and thus to the 5V power supply...
Some home appliances have a microcontroller directly tied to mains power and can use direct triac control. The disadavantage is that the microcontroller circuits and all switches, displays, sensors etc. must be protected against accidental contact like high voltage circuits. Testing and debugging a circuit with direct mains connection needs spec
That means you need a zero-cross optoisolator triac driver (MOC3083) then you might use a simple 555 to generate a PWM signal with very low frequency (T=few seconds) to drive the optotriac. This way, the voltage applied to your heating element will be half waves multiple thus there will be no stress on the mains power supply.
"Dimmable" LED power supplies are expected to work with regular triac dimmers. The LED brightness should be independent of AC input voltage, the power supply is sensing the dimmer phase angle. No idea how good it works, just try.
The transistor circuit that drives the gate also should connect to pin 1. Yours does not connect to pin 1. Then your connection to the gate is floating and does nothing. The transistor in an opto-isolator connects to the gate and also connects to pin 1 of the triac. How do you prevent somebody (or yourself) from being electrocuted withou
Use an opto triac. An opto triac will 'hard fire' the main triac. ( Edit - this applies to triacs. I've not used it with Thyristors but I suspect the following still applies ). A hard fire means that the triac gate is ALWAYS being driven when required to be on. Soft trigger is the transformer type - (...)
I design a board with 3 triac output. The power supply is 220VAC and i want to give 150VAC to a load. The load i a switching AC/DC load with power max cons. 40VA. I detect zero cross and i trigger the MOC for 1ms only. The problem is that after some times a triac is "burned". I am using the (...)
A three phase 440V 63 A contactor will need a inrush drive of 100W, with a holding power of 20W or so. You can drive this via a solid state relay which will contain a opto isolator and a triac and will require something like 5 V at 20 mA to operate it. The real problem is that the contactor coil will require a supply when the mains is (...)
If you can specify the resistance or impedance of your heat electrode, then you can determine what voltage you need to apply to dissipate 1.5kW. Most likely you can use triac control AC or cycle count burst control using a ZCS triac with suitable driver.
Hi guys, I have searched forums to no avail, so I figured maybe you could help. (I am an absolute novice) I have two wires which have DC current flowing through them. One has 5V DC at 500mA, and the other ranges from 10mV to 3.3V with a small varying current. The current has to flow in two directions for that second wire which is hooked up to so
I'm doing a project and want to use a microcontroller to control an LED from 230Vac mains. What I'm looking for is an LED driver that can be digitally controlled (i.e. PWM for dimming) but that operates with ac mains. Most of the drivers I can find seem to only achieve dimming using a triac rather than PWM. Could anyone point me in the right d
It's better you use a transformer along with the triac or use SMPS circuits. Since this is for a battery charger, isolation is a must. Otherwise, upon touching a battery terminal, you'll receive a nasty shock. This is not allowable for battery chargers, especially if the battery is not sealed inside a box or case. You can use a transformer rated
Hi! I'm working on designing a touch button using pico power AVR microcontroller. upon detecting a touch, the system should activate an AC appliance. For that i will use a triac. The whole circuit should consume no more than 1 mA at 2V. Now I'm searching for the best way to power this circuit from the AC mains without using a bulky (...)
Subject says it all, really. I am a little out-of-my-league when it comes to triacs and SCRs. The power supply is a square wave and I cannot get the triac to turn off. I suspect it has to do with the fact there is no zero-crossing or that the load is capacitive but don't know how to fix it. Here's the circuit: (...)
I need to control a a load (heater) using a triac. I need to use something like pulse skipping modulation to control the heater. The Microcontroller board and Analogue part will be working from a +12-0 -12V transformer based power supply. I think I can use the DC before filter with a transistor arrangement to trap the zero crossing point for (...)
if constructed the circuit then conect a 100watt bulb in series with the regulator vary the pot . then also their is no dimming then their will be the fault on diac/triac
if R3 is not added, the 2N3906 will break down for unknown reason . . . Look sharp and write obvious instead of unknown. Actually, you have two options: 1. Connect DC power supply GND with triac A1 terminal. Requires either an isolated supply or rearrangement of the AC load. 2. Use an optotriac for (...)
Anytime i want to build some power supply i have to have a there any solution to build some power supply without using a transformer?I was thinking about an pwm regulated power supply which uses triac(s) and the current coming right from the main source ( 230 V 50Hz).Does (...)
Hi I have to design a cicuit diagram. design a circuit diagram on change-over switches which is i can build it in the lab which is include in the circuit two switches, using current sensor(important), power supply, two load to test your switches, microprocessor to control switches( so u need a program), MCB and triac.....etc. (...)
Hi. I'm trying to use an MOC3021 opto triac to switch On/Off a little power supply(the 230 V side). I want to use it for direct load switch, not using it as a driver to a second triac. In MOC's datasheet it is a "warning" such that: "This optoisolator should not be used to drive a load directly. It is intended to be a (...)
Can I use triac used in the dimmers for lamps and fans to produce 12V. Ripple factor is not so important. I just want to charge a 12V battery with 10A current. I will select the firing angle at a point such that the average value of the output will be 12V. Then I will use full wave rectifier. Is it possible? I think triac used in this way is analo
I assume the 'high power' of the DC motor is 'DC power supply'. If it's DC power supply, probably you could use MOSFET or IGBT to replace the triac. Can you have that option?
The power supply is very simple ( no transformer based) so all the circuit isn´t isolated, and for that reason i don't need an optotriac (reduces project costs). There is another problem... the gate current must be over 50mA... for opto diac the command curent is reduced to 5-10mA. Your power source is enough to (...)