Circuit is correct or not

Status
Not open for further replies.

rajaram04

Advanced Member level 3
Joined
Jun 17, 2012
Messages
871
Helped
6
Reputation
12
Reaction score
5
Trophy points
1,298
Location
earth
Activity points
7,687
Hello sir

here is a circuit shown below . . please tell is it o.k. ot not ? Will it work or fail or may cause damage ?

Too how much voltage & current approximatly it is producing




If you the circuit is incorrectly designed at input stage please tell what changes we ll have to apply ?
 

Scariest circuit I have not seen recently.



AC voltage is rectified by the full wave rectifier formed of D1 through D4.The rectified voltage is reduced to a safer level by the resistor R1.The low volt DC is then made ripple free by C1 and regulated to 5 volt DC by the Zener diode ZD. Transistor T1 and T2 form an oscillator with capacitor C3 and resistor R2. The charging and discharging of C3 through R2 makes T1 and T2 oscillating.LED connected to the positive of C5 flashes depending on the charge and discharge of C5.When C3 fully charges, T1 conducts and its collector pulls the base of T2 to ground and it also conducts. This causes the discharge of C5. When C3 discharges, T1 and T2 turns off and now C5 charges through R4.This causes the Flashing of LED.

Caution: Shock Hazard! This circuit is directly connected to High volt AC. Do not construct the circuit if you are not experienced in handling AC voltage. Do not touch any points when connected to mains.

https://www.electroschematics.com/5604/led-flasher/
 

well it might work but i dont think is at the safer side due to 22k current limiting resistor it's going to generate more heat and it will end up getting burnt with time ,i will prefer step down transformer instead.
 

The 22k resistor will have very high peak voltages across it and it will arc producing a burnt line which keeps on conducting until the circuit blows up.
 







so sir as per you its not good at all ? i shud not go for it ?
 

This circuit is perfectly alright to work with. Instead of using a 1W 22K res which will heat up in due time, on the ac side use a step down transformer.
 

rajaram04 said:
i shud not go for it ?
Click to expand...
No, you should not.
You will be electrocuted if you touch any part of that circuit when it's switched on. Also R1 will burn out after a short time and may start a fire.
 

rajaram04 said:
so sir as per you its not good at all ? i shud not go for it ?
Click to expand...

RajaRam I suggest using transformer or isolated SMPS for any your project.

In addition to electric shock and fire due to inadequate components, components value or their position and orientation in the circuit, part exploding can happen and some sharp particles can hit right in the eye.

If you dont know where to get small transformer or smps: Cheap small iron transformer for small project can be extracted from cheap chinese wall adapter. On the same way you can get small SMPS, take PCB from some chinese phone charger.
 

I hope, unused charger of mobile decide problem electrical hazard and R1 burn out. The more so that the power dissipated in R1 is 0.01A*220V=2W not 1W, as indicated in the diagram, which is a direct diversion.

Simple remove rectifier, ZD and R1 and connect charger with the correct polarity. You can also reduce the operating voltage of the capacitors to 10V.
 
Last edited:

arunava7 said:
This circuit is perfectly alright to work with. Instead of using a 1W 22K res which will heat up in due time, on the ac side use a step down transformer.
Click to expand...



kk so as per you what should be that in place of 22k ?

- - - Updated - - -

pplus said:
I hope, unused charger of mobile decide problem electrical hazard and R1 burn out. The more so that the power dissipated in R1 is 0.01A*220V=2W not 1W, as indicated in the diagram, which is a direct diversion.
Click to expand...



kk so the 22k is alright here ? you mean i hv to use 22k 2w resistor in place & rest of the circuitry is o.k. ??????????????
 

As has been said here before, I would not do a device without galvanic separation from the mains but if you want to take risks I'd take R1 power 5W
 

Why don't you go for a easier and safer LED flasher circuit...just google it and you'll find lots of them.
 

arunava7 said:
Why don't you go for a easier and safer LED flasher circuit...just google it and you'll find lots of them.
Click to expand...


yess the basic reason is not the flasher light here . I just want to use the supply for driving small basic circuits as here shown in figure a flasher unit may be in astable mode it means this are also able to drive other small circuits na . . that i am designing so collecting all this from diffrent units of electronics . . actually i want a circuit running on mains & can drive this small circuits using transistor & all small devices
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…