Fascinating reading: http://www.irf.com/technical-info/appnotes/an-948.pdf (found from here: ...

Fascinating reading: http://www.irf.com/technical-info/appnotes/an-948.pdf (found from here: http://sound.westhost.com/articles/hexfet.htm) I've heard that the 2SK1058 is superior for audio, and is the only MOSFET spec'ed in Slone's book, but that this MOSFET is currently now unobtanium. What is the purpose of the inductor L1 (3 uH, air core) in series with the speaker? Any commen...

The only problem that I may have created is the transistor, I used BC547B with HFE of 200 to 450 vs BC549C with HFE of 420 to 800. All I had...

The only problem that I may have created is the transistor, I used BC547B with HFE of 200 to 450 vs BC549C with HFE of 420 to 800. All I had in my junk box. I built a low noise amplifier, original design was for a 30v supply, I chose to correct the values for a 15V supply. Designer does have a 12v version, my values are close.  I did set an emitter resistor to have equal clipping....

Q. Relative power dissipation capability of TO-92 transistor packages (viz, Zetex E-line parts) vs. sot-23 packages. More on this in my...

Q. Relative power dissipation capability of TO-92 transistor packages (viz, Zetex E-line parts) vs. sot-23 packages. More on this in my next post, first some background. One of my design interests is high-frequency, high-voltage power amplifiers. For example, I'm doing a 45V, 5A peak, DC-10MHz amplifier. My design uses 20 TO-220F power transistors, mounted on a 200W fan-cool...

Does anyone use Apex parts? https://www.mouser.com/c/semiconductors/amplifier-ics/operational-amplifiers-op-amps/?marcom=184 808364 The...

Does anyone use Apex parts? https://www.mouser.com/c/semiconductors/amplifier-ics/operational-amplifiers-op-amps/?marcom=184 808364 The companion heat sink is https://www.mouser.com/ProductDetail/Apex-Microtechnology/HS11?qs=TiOZkKH1s2RwK46pUwsmlQ%3D%3D -- If a man will begin with certainties, he shall end with doubts, but if he will be content to begin with doubts he shall end

Inspired by the late Jim Thompson's autobias design that we saw in the thread "Power Amplifier for 100kHz" I thought his use of a bang-bang...

Inspired by the late Jim Thompson's autobias design that we saw in the thread "Power Amplifier for 100kHz" I thought his use of a bang-bang comparator in setting bias was non-optimal but I liked his idea of running the pa in pure class B for large signals and setting a minimum quiescent class A current for small signals. My idea uses JT's way of sensing output device current falling bel...

What is the most powerful vacuum tube ever made? I'm looking into building the most pewerful tube audio amplifier possible. I'll be using 4...

What is the most powerful vacuum tube ever made? I'm looking into building the most pewerful tube audio amplifier possible. I'll be using 4 tubes in push-pull parallel. (per channel). My goal is at least 5000 watts RMS per channel (if possible). I will likely rewind some pole pigs (power pole transformers) for output transformers, and possibly use one of them in reverse for the power supply...

I need to select a capacitor for a battery pack. I see a lot of circuits that use Alkaline batteries and then have a ceramic capacitor across the...

I need to select a capacitor for a battery pack. I see a lot of circuits that use Alkaline batteries and then have a ceramic capacitor across the leads of the series battery pack to act as a filter. My question is how do you size the cap ? I hate just looking at what someone else has done and just guess or copy. I have 4x 1.5v alkaline batteries in series powering a amplifier circuit. ...

I became discouraged of finding a suitable low-capacitance zener to protect the MOSFET gates in my high-voltage amplifier designs. (The...

I became discouraged of finding a suitable low-capacitance zener to protect the MOSFET gates in my high-voltage amplifier designs. (The protection may be optional, but one sleeps better with it in place.) Even the 50uA-rated low-current zener diodes are in fact larger-die types, with high capacitance. For example, the 7.5-volt MMSZ4693 has about 130pF at zero volts. My solution was to us...

Dear All, I am building a PWM Sine Wave Inverter using H-Bridge IGBT Configuration. The inverter has the following stages: 1. A Sine Wave...

Dear All, I am building a PWM Sine Wave Inverter using H-Bridge IGBT Configuration. The inverter has the following stages: 1. A Sine Wave Oscillator 2. An unity gain inverting amplifier to generate inverted sine wave 3. A Triangular wave generator 4. Two Sets of Comparators to generate PWM waveform for positive and negative cycles 5. Two Half Bridge IGBT Drivers to generate A and A' s...