Comparsion among triac, relay and transistor

[Raghunadh]

Good Evening,

In a Project I am using a dimmer module designed by sunrom technologies to control the intensity of a bulb upto 3 levels such as ON, OFF, LEVEL25 AND LEVEL75. on searching i came to know about this module that it is good for intensity controlling. Please tell me other benefits by using this module with comparing to a Relay or Transistor.

Please anyone can tell me is it possible to control the intensity of bulb by using a Relay and transistor. If it is possible please tell me the basic operation.

Thanks in Advance.

 

[tpetar]

MosFET - Dim 12V Light Bulb with 555 IC Project Circuit
**broken link removed**

**broken link removed**

Triac - Electronic Lamp Dimmer Circuit
https://www.electroschematics.com/2062/electronic-lamp-dimmer-circuit/

**broken link removed**


With relay you cant direct dimm the light, but you can switch some other circuit which will do the job.

For transistors and ModFETs its very improtant maximum allowed voltage. Also power dissipation will be high in some situations.


Best regards,
Peter

 

[BALKRISHNA TULSYAN]

with relay it is not possible to control the intensity but with transistor u can do it. for best case you use power transistor like Z44(MOSFET) or 3055(BJT) because power transistor can sustain more heat by using heat sink. connect variable resistor to the base of transistor and change the resistance when circuit is on.

 

[tpetar]

What if he need to dimm mains voltage bulb 220V/110V, will 2N3055 or Z44 handle this ?

For lower voltage ok. :smile:


:wink:

 

[BALKRISHNA TULSYAN]

3055 can sustain up to 100 volt. For higher voltage application like Mains bulb dimming u can use NTE379 NPN transistor. This can hold up to 400 volts

 

[tpetar]

If capable to dissipate that power.

 

[shegzzyy]

You can use scr instead of transistor

 

[BALKRISHNA TULSYAN]

@tpetar : NTE379 is particularly suited for 115 and 220V switch–mode applications such as Switching Regulators, Inverters, Motor Controls, Solenoid/Relay drivers, and Deflection circuits. So according to me it can handle that much power. what u say?????

 

[tpetar]

According to datasheet NTE379 can dissipate 100W at Tc 25C. This can be enough for lots light bulbs if Tc is keept in some normal range. However its hard to keep Tc at 25C. ;-)

Also consider power dissipation as losses in energy and compare triac vs transistor + temperature as product. With other words, how to dimm with lower losses and heat. For me Triac is solution, but of course its good to hear other opinions.

 

[BALKRISHNA TULSYAN]

What if i am using collector to base biasing to avoid thermal runaway?? Moreover 100 watt at 25c will work fine for ac bulb less then 100 watt.

 

[deepmak]

Hello ,
dimming light working on 220 vac can be done using Diac and Triac , i found such circuits online , here is one sample

also i i believe this can be done using SCR with control of gate trigging angle or PWM