T&L Publications

What Chris may mean is to slow the frequency down to very slow frequency and keep the pulse width the same as it was at the 50khz to observe what happens when the duty cycle is reduced to less than 1%. Once I reduced it so low that even though the core was saturating, it did not overheat the mosfets...

Maybe you can get some ideas from my yahoo thing also http://groups.yahoo.com/group/switchmode/ <p>If all else fails, try converting the configuration to half-bridge like I always use. You won't get imbalance problems as the capacitor keeps the output in balance. You would only be able to use one pr...

Try putting a current limiting resistor in series with each MOV, maybe about 10 ohms.<p>I have wondered if built-in zeners could cause an inductive spike on the gates. Try mosfets without them.<p>Like Stephen said, the Miller effect can cause the mosfet that is supposed to be off to be turned on if ...

My mom had once noticed that some plumbing parts had the Jameco brand name on them when they were being installed in her house years ago. She was struck by that fact because she had often heard of my ordering electronic parts from Jameco. We discussed the possibility of there being two seperate comp...

I am planning to do basically the same thing for an electric bicycle project. I am going to base it on the universal power supply circuit. Instead of using closed loop feedback as shown in the schematic, a potentiometer can be connected to the power supply output shown. Just run the output of the po...

Here are some further thoughts. The June _Nuts and Volts_ issue just had a very simple circuit for doing this project. It is built around DPDT relays. If you would like this circuit email me and I will try to send it to you.<p>However, in the vein of Edd Whatley's idea using SCR's, Bill Bowden has a...

Also, your speaker probably has poor response that low. Therefore, it may only respond to the higher harmonics of a square wave input.

Yep, that is what it boils down to. What Dean may attest to is that there is not enough teaching in the US on basic circuit theory, but too much emphasis on using or maybe assembling computers.<p>Much of the lack of knowledge of circuit theory is traceable to the advent of surface mount components i...

Transformers are a major device in most DC to DC converters. Those circuits basically chop the DC voltage, pass it through a capacitor to convert it to AC, feed it into a transformer to change the voltage, then pass it through one or more diodes to convert it back to DC. The voltage output will appr...

For increasing voltage more than a couple of times, a converter using an inductor is simpler. But then, it is often more practical to use a transformer, which is two or more inductors magnetically coupled together.<p>If you just want to roughly multiply voltage, the easiest way I know is to use a ha...

The easiest way to get negative voltages is by means of a charge pump. You charge a capacitor, then pull its positive terminal low, and lastly capture the negative pulse from the negative terminal with a diode. Then you can run that voltage after filtering through negative regulators.<p>Did you know...

Ok, hmm...I was thinking the ATX power supply was using a MOSFET totem pole to drive the power transformer. It may more likely use another way like flyback.<p>I tend to like the possibility of running the ATX power supply off of the inverter. You may possibly be able to increase the efficiency of th...

With yor first idea, one thing to be sure to check first is how the AC power input to your ATX is handled. Many computer SMPSs have a 120/240 switch. If yours has such a setting option, then the DC supply to the power MOSFETS will be 320 volts. If you try to operate it on +60, -80 volts, those MOSFE...

If frequency accuracy is not important there are two ways I would consider. One would be to run a class D amp at 400 Hz with 320 volt peak-peak output. The output is neither isolated or a sine wave, but by limiting the duty cycle, it may work well enough.<p>The other way should overcome the limitati...

I like the demo version of MicroCap because even a slow learner like me can use it easily.