0
\$\begingroup\$

Here is Wien Oscillator circuit:

enter image description here

Amplitude of oscillations, Vout, is about 10V. If I put step up transformer on output with appropriate primary/secondary ratio, I can get 220V AC voltage, and it would be some basic DC to AC inverter, right? But because of small output current of LM741, it can't be used to power bulb for example?

\$\endgroup\$
  • 1
    \$\begingroup\$ Right, and right again. Note that if you step voltage up 20:1 you also step current down 20:1, so if the 741 can supply 20mA (optimistic) you could expect 1mA at 220V which is practically useless. \$\endgroup\$ – Brian Drummond Dec 9 '15 at 21:42
  • 1
    \$\begingroup\$ NO, just slapping an oscillator and a transformer together does not make a DC to 220V AC inverter that can power a lightbulb. Have a look at some of the many schematics you find if you google on: "power inverter schematic" and then select "images" (instead of websites). Note how the circuit that drives the step up transformer is never just a 741 opamp. \$\endgroup\$ – Bimpelrekkie Dec 9 '15 at 21:42
  • 1
    \$\begingroup\$ Right. Power, not voltage or current, is conserved. So a +/- 10 volt output is about 7 volts RMS. A 741 can put out about 10 mA. Power available is then 7 x .01, or 70 mW. So, well, you can drive a light bulb - as long as it's a 70 mW bulb, and those are hard to find. \$\endgroup\$ – WhatRoughBeast Dec 9 '15 at 22:33
  • 1
    \$\begingroup\$ Like using a candle to boil a kettle. \$\endgroup\$ – Andy aka Dec 9 '15 at 22:44
  • 1
    \$\begingroup\$ Regarding the headline: Where do you see an "inverter"? The WIEN oscillator needs a minimum gain of +3 (1+22/10=3.2).. \$\endgroup\$ – LvW Dec 10 '15 at 6:27
2
\$\begingroup\$

This is very impractical.

1) The sinusoidal signal generated is not efficient for power generation -- because it uses a linear amplifier to convert the supply power to the sinusoid.

2) A light bulb would be perfectly happy with a square wave, and this can be generated much more efficiently.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.