LC_Tuning-Outside_the_Box

Started by Jim Thompson in sci.electronics.design8 years ago 70 replies

Tuning an LC can be done in a continuous fashion using feedback... add in a SIGNED (or variable phase) percentage of the tank's...

Tuning an LC can be done in a continuous fashion using feedback... add in a SIGNED (or variable phase) percentage of the tank's output, see... But observe... (1) E1 will (in this case) need to be about a 10W amplifier... but not a particularly difficult task at 100kHz (2) Clever souls will realize that you can au


CFA question

Started by ***Marco*** in sci.electronics.design7 years ago 9 replies

Hi all, I've a silly question because I'm a bit unexperienced with current-feedback amplifiers. I've observed from both the datasheet and...

Hi all, I've a silly question because I'm a bit unexperienced with current-feedback amplifiers. I've observed from both the datasheet and from experimental data that the closed-loop frequency response rolls off with -40 dB/dec, while I'd have expected a -20 db/dec. I'm using Analog AD811 configured as a non-inverting amplifier with gain 5. Is this behaviour common to CFAs or is it typi...


OT: Class D Amplifier Design

Started by Cursitor Doom in sci.electronics.design5 years ago 133 replies

Hi all, Please excuse this off-topic posting which doesn't involve US politics at all. I was just wondering what the efficacy of class D...

Hi all, Please excuse this off-topic posting which doesn't involve US politics at all. I was just wondering what the efficacy of class D amps is when applied to the design of hi-fidelity audio amplifiers? I can't help thinking their functional limit would be public address systems where a fair amount of distortion can be tolerated, not to say expected even. But is it feasible to desi...


Stabilizing pHEMTs

Started by Phil Hobbs in sci.electronics.design10 years ago 65 replies

So, JL's thread about level shifting a pHEMT switch brings up another issue: stabilizing the silly things. I have this little SKY65050 preamp...

So, JL's thread about level shifting a pHEMT switch brings up another issue: stabilizing the silly things. I have this little SKY65050 preamp that works very well--about a nanoamp of input current, 0.5 nV/sqrt(Hz) noise in the flatband, 0.8 pF Cin, flat from DC to about 120 MHz where the THS3091 second stage craps out. A very nice amplifier, but for the intended use, it could stand a bit ...


synthetic resistor

Started by John Larkin in sci.electronics.design3 years ago

We want to bias up a 3-stage 20 GHz distributed amplifier. It's tricky and the chip costs $150, so we don't want to blow it up. A good...

We want to bias up a 3-stage 20 GHz distributed amplifier. It's tricky and the chip costs $150, so we don't want to blow it up. A good drain source might be a 50 ohm resistor from +16 volts, but clamped to +10 just in case. This does it: https://www.dropbox.com/s/mkk3q2q7pznopqj/317_Soft_1.jpg?raw=1 If K=1+R3/R2, Reff = K*R1 Veff = K*1.25 and it clamps when the reg runs out of...


AC and DC Current Sensing

Started by panfilero in sci.electronics.design8 years ago 59 replies

I'm interested in sensing AC and DC currents, 0-8A nominally, but up to 160= A for 10msec current surges from both AC and DC sources... I'm after...

I'm interested in sensing AC and DC currents, 0-8A nominally, but up to 160= A for 10msec current surges from both AC and DC sources... I'm after the be= st resolution I can get... I don't know if it's possible to do this for bot= h AC and DC off the same current sense circuit... I was thinking a shunt th= rough a current sense amplifier then to an RMS to DC converter IC... but I'= m not sure...


Abusing the LM386

Started by bitrex in sci.electronics.design4 years ago 77 replies

Use two bridged to drive say a little PCB-mount 2k - 8 ohm audio transformer "backwards" to charge a HV capacitor, current feedback from each...

Use two bridged to drive say a little PCB-mount 2k - 8 ohm audio transformer "backwards" to charge a HV capacitor, current feedback from each side of the "primary" inductance keeps the drive current waveform from going all sloppy, cross-coupling the G1 pins boosts each amplifier's "open loop" gain.


Heatsink problem

Started by Clive Arthur in sci.electronics.design3 years ago 22 replies

I have some equipment which uses a power amplifier (15 lead TO-220) mounted on one of these on a...

I have some equipment which uses a power amplifier (15 lead TO-220) mounted on one of these on a PCB... http://www.farnell.com/datasheets/2058000.pdf No problems until now, it runs cool because the duty cycle is low, in fact it would be fine without a heat sink, I just need the power for a few percent of the time. However, a new customer wants to use the equipment in an unusual mann...


Reconstruction of a ceramic wafer switch.

Started by Jamie in sci.electronics.design10 years ago 8 replies

Like the title states. I have not done this for a long time and the last time I did I only needed to repair just the wiper fingers. Well,...

Like the title states. I have not done this for a long time and the last time I did I only needed to repair just the wiper fingers. Well, this time I need to reconstruct most of the wipers on one ceramic wafer and the shorting plate. This is for an old SB-1000 Linear Amplifier, It also looks like some one with very little skills in the field attempted repairs on their own by loo...


Comparator as operational amplifier

Started by Klaus Kragelund in sci.electronics.design5 years ago 25 replies

Hi So as always, I am looking for the last cent I have a design where I need a pretty fast opamp, something that settles the output within 1...

Hi So as always, I am looking for the last cent I have a design where I need a pretty fast opamp, something that settles the output within 1 us I have a free 25ns propagation delay comparator in the design, so I thought I could trick that comparator into changing gender to a opamp So first attempt was this: https://www.dropbox.com/l/scl/AAA0Q564c4zABf23i2HmIUbsbcyWmFTynLs (


HDMI connectors

Started by Phil Hobbs in sci.electronics.design9 years ago 23 replies

Hi, all, I'm just finishing the details on a front end amplifier for a semiconductor equipment vendor. It's in a fairly ugly EMI...

Hi, all, I'm just finishing the details on a front end amplifier for a semiconductor equipment vendor. It's in a fairly ugly EMI environment, with a bunch of switching motor controllers nearby, so I'm shipping the analogue output as a shielded differential signal. For reasons of price/performance, I'm considering using a single normal-size HDMI connector for everything. Any wisdo...


IcePower module

Started by Phil Allison in sci.electronics.design2 years ago 39 replies

Hi to all my fans, just completed repairs on one of these: http://www.sound-power.ru/files/doc/ICEpower125ASX2_datasheet.pdf Found it...

Hi to all my fans, just completed repairs on one of these: http://www.sound-power.ru/files/doc/ICEpower125ASX2_datasheet.pdf Found it fitted inside a mini-size bass instrument amplifier, which the owner had just purchased over the net and failed on him at first power up. Smelling a rat, I checked the AC switch on the rear panel first - blow me down, it was set to 120VAC


Anyone have an MC34063 SPICE model lying around?

Started by Tim Wescott in sci.electronics.design10 years ago 4 replies

Title says it all. LTSpice preferred. While we're on the subject -- does anyone know what the error amplifier gain is in the MC34063, and...

Title says it all. LTSpice preferred. While we're on the subject -- does anyone know what the error amplifier gain is in the MC34063, and what ranges one can expect in real life? The data sheets all call it a "comparator", but reading between the lines it's a gain stage followed by a comparator to the oscillator (which is what it has to be, to work correctly). -- My liberal frien...


stunningly stupid Electronics Design article

Started by John Larkin in sci.electronics.design3 years ago 63 replies

https://www.electronicdesign.com/analog/closer-look-common-emitter-amplifier-and-emitter-followe r -- John Larkin Highland...

https://www.electronicdesign.com/analog/closer-look-common-emitter-amplifier-and-emitter-followe r -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com


Guesstimate A Transformer

Started by Anonymous in sci.electronics.design3 years ago 14 replies

One of my useless things I think I'll throw together. An audio amp. I have transformers, audio output transformers from a tube amp that have a...

One of my useless things I think I'll throw together. An audio amp. I have transformers, audio output transformers from a tube amp that have a certain feature I need for this. This is a mobile audio amplifier. The basic configuration is shown at the end of this post in Spice. The coils, L1 and L2 are actually a center tapped winding. What I want to know is how much power dare


Vout Lo in LM324

Started by Marte Schwarz in sci.electronics.design10 years ago 48 replies

Hi all, I'm a little confused by this old companion... If I used an LM324 in amplifier applications it's all right the lower Voltage at...

Hi all, I'm a little confused by this old companion... If I used an LM324 in amplifier applications it's all right the lower Voltage at output is pretty low. Making an shmitt-trigger circuit the Low Voltage is only about 0.7 V. Does anyone have seen this, too? First I thought, I got faked parts, but actual I'm sure that I got origin parts from ST showing the same effect. I wanted to s...


Maxim Instrumentation Amplifiers

Started by DemonicTubes in sci.electronics.design5 years ago 51 replies

Does anybody here have experience with MAX4208/MAX4209? Current project is going to need an instrumentation amplifier, looking at my inventory...

Does anybody here have experience with MAX4208/MAX4209? Current project is going to need an instrumentation amplifier, looking at my inventory all I have is some through hole INA111 that still have Burr-Brown stamped on them (probably bought them in the mid 90s)...time to upgrade my stock! As I go see what's new I find the Maxim MAX4208 and MAX4209. Normally there seems to be a


GaN RF Amp Linearizer

Started by mpm in sci.electronics.design2 years ago

Quick question if anyone knows... Could a linearizer be used on a GaN amplifier that is amplifying more than one RF channel at a time? For...

Quick question if anyone knows... Could a linearizer be used on a GaN amplifier that is amplifying more than one RF channel at a time? For example, 3GPP Band-2 Simultaneous 1940-1950 MHz, and the maybe 1960-1965 MHz? (Both LTE in this example, but what if the higher one were UMTS?) What I really want to know is A) will this ever work, and B) if it can be made to work, how muc


Gate resistor for lateral power MOSFET?

Started by Frank Miles in sci.electronics.design5 years ago 26 replies

I'm designing a power amplifier using some Exicon lateral MOSFETs as the final common-source stage. These will be used in various experimental...

I'm designing a power amplifier using some Exicon lateral MOSFETs as the final common-source stage. These will be used in various experimental systems. Each only needs to run around +/-50V out, up to 4A, and driving sinusoidally between 50 and 400kHz. The load can be approximated as a lossy series LC circuit, driven near resonance with R generally 10-20 ohms. There's an additional > 200


capacitor selection

Started by Jon Elson in sci.electronics.design9 years ago 37 replies

Hello, all, I have been using metallized polyester film capacitors in the output filter of a PWM servo amplifier. I recently discovered that...

Hello, all, I have been using metallized polyester film capacitors in the output filter of a PWM servo amplifier. I recently discovered that when the PWM duty cycle is near 50%, these caps can get quite hot. Perusing the data sheet, it appears that I am running above the manufacturer's current rating in that condition. Can anyone recommend a capacitor around 10 nF and 250 V DC rating t...