Inverter.........!

[koolguy]

pls tell...!

 

[chemelec]

sir, from where this 1.414 constant value you have taken from, and in ltspice software to make transformer circuit it ask how much impedance of sec. and primary coil , pls tell relation between no. of turn's and impedance.

Ratios of these Are EASY.
"Turns Ratio" = Square Root of the "Impedance Ratio".
So "Impedance Ratio" = "Turns Ratio" Squared.

But I believe the "Actual Impedance" will Depend on Coil Inductance and Frequency of Operation.
NOT SO EASY!

 

[koolguy]

But I believe the "Actual Impedance" will Depend on Coil Inductance and Frequency of Operation.
NOT SO EASY!

so, what about the option given in LT spice software for transformer designing for giving output.

 

[chemelec]

IF you Know the Correct INFO, Just Enter It.
What more can I say!

 

[koolguy]

sir, you have not design circuit in lt spice software, or in other software.

 

[chemelec]

sir, you have not design circuit in lt spice software, or in other software.

I Rarely use Any Spice Programs for any designs.
I Design and Test Using REAL Parts.
It is the Only way to know for SURE, that a Circuit Really Works.

And I probably Have over 100,000 Parts in my stock.

 

[audioguru]

If you are making a very simple square-wave inverter then use a CD4047 for the oscillator instead of a 555. The CD4047 has a digital divider that makes both a true and an inverted outputs that make a perfectly symmetrical square-wave. A 555 does not make a perfect square-wave easily and needs to have an additional inverter to make the inverted output.

 

[koolguy]

i was making inverter for this i have taken output from 555 ic with darlington in common collector mode, i tested different frequency and when connected the output to secoundary of transformer it was showing 8v in one transformer and in another it show's zero , pls tell procedure and mistake i have done in this circuit as i have tested the output of 555 ic with multimeter.

the transformer were of 18v and 14v RMS.

 

[audioguru]

A common-collector transistor is an emitter-follower with no voltage gain. It boosts the current but has a DC voltage drop of 1.25V to 2.0V.
Its output is a varying DC voltage that you should not feed to a transformer.

The darlington transistor is probably destroyed by the high voltage spikes produced by the inductance of the transformer.

The 555 has a simple rectangular-wave output. Why are you boosting the current then feeding a rectangular-wave DC pulses into a transformer? A power transformer usually has an AC sine-wave for its input.

 

[koolguy]

I am making very simple inverter for small load like CFL, I have also used common emitter but it was not boosting current and pls tell is there is any difference in gain of transistor when operating in forward-forward bias and reverse-reverse bias.

as, i was using reverse-reverse biased in darlington it was not working pls tell...!

 

[audioguru]

I am making very simple inverter for small load like CFL, I have also used common emitter but it was not boosting current and pls tell is there is any difference in gain of transistor when operating in forward-forward bias and reverse-reverse bias.

as, i was using reverse-reverse biased in darlington it was not working pls tell...!

Post your schematic.

 

[chemelec]

I am making very simple inverter for small load like CFL, I have also used common emitter but it was not boosting current and pls tell is there is any difference in gain of transistor when operating in forward-forward bias and reverse-reverse bias.

as, i was using reverse-reverse biased in darlington it was not working pls tell...!

I DOUBT CFL's Will work with a Square Wave Inverter.

But either way you should Post Your SCHEMATIC!

 

[koolguy]

sir, it is simple 555 ic in multi-astable mode, and darlington BU508D in r.b. - reverse bias mode is not working.

 

[audioguru]

Without seeing your schematic then we don't know what you are doing.

 

[chemelec]

I Totally Agree.
Show the Schematic!

And What is with this Reverse Bias?
If your Driving the Transistors with a Square Wave, It is Unlikely you need ANY BIAS.
The Transistors will be Either ON or OFF.

 

[koolguy]

I Totally Agree.
Show the Schematic!

And What is with this Reverse Bias?
If your Driving the Transistors with a Square Wave, It is Unlikely you need ANY BIAS.
The Transistors will be Either ON or OFF.

this is the circuit of reverse-2 biased and forward-2 bias.

 

[chemelec]

WHAT is an ASC Extension?
I Can't View these.

How About Posting a "JPG or GIF" File?

 

[audioguru]

Your transistor circuits are both WRONG.
1) The first transistor might have its base-emitter forward-biased if the V1 voltage is 0.7V or higher but the transistor does nothing because the emitter voltage and the load's supply voltage are the same at 0V.
2) The second transistor has no base-emitter bias voltage because they both have the same voltage. So the transistor does not conduct and is turned off. The voltage at the load is backwards.

I corrected your schematics:

 

[audioguru]

WHAT is an ASC Extension?
I Can't View these.

It is from LTspice IV which is a free simulation program from Linear Technology (the linear IC manufacturer).
He is using its schematic drawing part.

 

[koolguy]

Your transistor circuits are both WRONG.
1) The first transistor might have its base-emitter forward-biased if the V1 voltage is 0.7V or higher but the transistor does nothing because the emitter voltage and the load's supply voltage are the same at 0V.
2) The second transistor has no base-emitter bias voltage because they both have the same voltage. So the transistor does not conduct and is turned off. The voltage at the load is backwards.

I corrected your schematics:

you are right sir, my practical circuit was also same in hurry i made connection wrong but second fig. of transistor zero bias of transistor should be a pnp transistor not npn, i thick so.