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555 inverter brightness and over current issue
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dave_j_fan:
hi experts,
 I have used  this 555 circuit for very simple inverter
 
 https://www.eleccircuit.com/220-volts-power-inverter-using-ne555-and-mosfet
i am  running it  on dual 18650 i.e. approx 7.4v
for portability we cannot change this . It has to be 2 battery system .
MOSFETS are Z44.

observation
1) with 12 - 0-12 , 2 AMP transformer coil resistance 2.5E.  The inverter works very nicely
300mA current and ok brightness  ( just one winding i use 0-12 and one MOSFET )
so we get  7hour backup. This is fine

2) As the . 12-0-12 is bulky
  we used 0-6V/ 220V small 500ma transformer .
 coil resistance 12E
 But here it consumes 550mA 
 bulb is not bright too .


What can be the reason of increased current  .
i have  measured coil voltage to MOSFET its approx 3V







 

 
Zero999:
A schematic would help. The site you've linked to has two MOSFETs, yet the circuit you've describe only has one.

My guess is you're overloading the transformer causing core saturation, hence the higher current and lower output power.

What sort of light is it driving? LED or incandescent?

My advice is scrap the inverter and replace the mains lamp with one which can be powered directly from DC. Two white LEDs in series and a linear current regulator will be much more efficient than an inverter and a mains lamp. It can be made even more efficient with a switched mode power supply for the LEDs.
dave_j_fan:
Reposting  the  same  ...
 here one MOSFET i use .  in  both cases

 1)with 12-0-12V 2 Amp transformer
 2)0-6 V ,500mA transformer

 load is  7W  led

 Both cases led is lit, in second case total current  550mA
 in 1  case its 300mA

 I want to make it work well in 500mA transformer. so that i can case it in smal case
 gets portable

 (Not interested to run DC LEDs .. so please dont advice )
dave_j_fan:
DC lamps to avoided 

 1) need to be remotely mountable
 2)DC LED and  additional circuits are wastage of time and work
 3)All DC led bulbs  available in our countr are Junk and cant  be used
 --

 need to run 5w or 7W led as these are super reliable by all leading  brands
 comes with nice cases
Zero999:
Why post an oversized picture with loads of empty space?

Core saturation doesn't cause the iron core to heat up. It results in excess current being drawn through the primary winding. It may or may not cause noticeable heating of the transformer winding, depending on the power dissipation and mass of the transformer.

DC LEDs can be mounted wherever you like.

DC to AC circuits are a waste of time and just consume more power.

Just make your own DC LED lamps.
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