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Type: Posts; User: albbg
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8th November 2019, 21:47
 Replies
 4
 Views
 444
Closed: Re: Noise Figure budget analysis for power combiner & divider
If you combine two identical signal, perfectly in phase they amplitude will double while the noise (uncorrelated) will sum in power. Theoretically you can gain 3 dB NF. In practice you will have a...

24th August 2019, 23:49
Thread: How can I measure this voltage and current?
by albbg Replies
 11
 Views
 617
Closed: Re: How can I measure this voltage and current?
I think you should evaluate to complicate the circuit and use two linear optocouplers (one for the voltage the other one for the current) in order to avoid the ADC (and possibly other components) to...

21st August 2019, 20:54
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 6
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 460
Closed: Re: Calculating electromagnet – magnetism vs heat
Possibly this theses could help:
https://scholarworks.rit.edu/cgi/viewcontent.cgi?referer=https://www.google.com/&httpsredir=1&article=1408&context=theses 
19th August 2019, 22:04
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 3
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 399
Closed: Re: Will I be able to drive LED with attached analog circuit ?
The LED wiring is not a problem, it will be always negligible with respect to R3
Form the datasheet of the LED and the value in your schematic I can expect a current IF=2 mA and VF=3 V roughly. With... 
18th August 2019, 21:08
 Replies
 3
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 334
Closed: Re: Toroids EMI suppression choce choice of core material ?
You can't use the specificed AL value at the frequency of 15 MHz to calculate the number of turns. If you have a look to the permeability vs. frequency graph you can see that at your frequency the...

17th August 2019, 22:01
Thread: dc motor theory question??? Maths
by albbg Replies
 4
 Views
 875
Closed: Re: dc motor theory question??? Maths
Please, find attached my solution.
155048
155049
About the shaft powet, it is Ps=w*T, that is Ps=52.4*40 = 2096W or 2.8HP
if the torque is 60 Nm we will have 32.6*60=1956W or 2.6 HP
I did... 
15th May 2019, 12:17
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 628
Closed: Re: MAX485 modifications. Need help to find out what does it mean.
I think (not sure) it specifies the carrier type: no suffix=tube, T suffix=reel. The sign+ means ROHS compliant
https://www.maximintegrated.com/en/products/interface/transceivers/MAX485.html#tab3 
20th March 2019, 13:07
Thread: RF Limiter not working as it should
by albbg Replies
 4
 Views
 404
Closed: Re: RF Limiter not working as it should
What you mean with " without biasing" ? DC level was 0 V, or the inductor was disconnected ?
The inductor must be conected to ground directly or through a DC power supply, otherwise the DC voltage... 
18th March 2019, 23:15
Thread: Output of Variable gain amplifier?
by albbg Replies
 11
 Views
 798
Closed: Re: Output of Variable gain amplifier?
Yes, if we call Vadd the added voltage to the input of Rn with respect to Vin (that is the voltage applied to the non inverting pin), then
Vout = Vin  Rf/Rn*Vadd
Ideally if Vadd=0 then... 
18th March 2019, 21:41
Thread: why does this simple program not work
by albbg Replies
 5
 Views
 737
Closed: Re: why does this simple program not work
You wrote "output=kpo+kio;" instead of "output=output+kpo+kio;"

8th March 2019, 22:23
Thread: Finding X of L for an inductor
by albbg Replies
 8
 Views
 1,289
Closed: Re: Finding X of L for an inductor
There is a little mistake in the Akanimo answer: sqrt(2500900)=40 ohm, then XL=60 ohm
Furthermore if you want to calculate alfa, we know that tg(alfa)=im(Z)/real(Z), that is tg(alfa)=X/R.
In our... 
7th March 2019, 13:06
 Replies
 10
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 988
Closed: Re: Need help with singlephase fullwave rectifier
FvM gave a good hint.
Having a look to intusoft's app. note http://www.intusoft.com/nlpdf/nl12.pdf, the centertap transformer seems to be obtained paralleling the primary of two single secondary... 
7th March 2019, 07:55
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 10
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 988
Closed: Re: Need help with singlephase fullwave rectifier
We can focus on the voltage on the secondary.
I think you could have some simulation parameter to tune, f.i. RELTOL.
As far as I can I'll try to simulate your circuit with microcap10 to see if... 
6th March 2019, 22:23
 Replies
 10
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 988
Closed: Re: Need help with singlephase fullwave rectifier
Unfortunately your calculation is not correct. I've got a rigorous mathematical derivation starting from the general case of mutual coupling.
Here is the results:
151534 151535 
5th March 2019, 13:13
 Replies
 10
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 988
Closed: Re: Need help with singlephase fullwave rectifier
Your calculation is correct: the coupling factor you used (0.99) can be neglected.
I think the scale of the graph you represent the output waveform is too wide. Try to plot the output waveform... 
3rd September 2018, 22:39
 Replies
 2
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 875
Closed: Re: What is the difference between characteristic impedance and normal impedance?
I think you mean "nominal impedance". The characteristic impedance is the actual impedance of the transmission line, while the nominal impedance is the impedance that should have the line by design....

24th July 2018, 17:38
Thread: PLL out of lock after several seconds
by albbg Replies
 6
 Views
 782
Closed: Re: PLL out of lock after several seconds
You have to check the output of R and N divider. It could be the level of the rf signal sent back to the pll is too low. Also investigate if the charge pump is working properly.

22nd July 2018, 21:14
Thread: 90 degree phase shifted magnetic fields
by albbg Replies
 4
 Views
 706
Closed: Re: 90 degree phase shifted magnetic fields
As far as I correctly understand your question, the signals to the primary coil are rectified, that means they are A*sin(wt) and A*sin(wt+90) (I supposed same amplitude).
In this case the 45... 
20th July 2018, 22:09
 Replies
 2
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 1,248
Closed: Re: How to convert the power EIRP 13.03 dbuv/m at 300m to dBm
dBuV/m is not a measure of power (or EIRP) but a measure of electric field E.
Considering the spherical radiation the electric field in far field can be calculated distributing the power over a... 
20th July 2018, 21:43
 Replies
 9
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 851
Closed: Re: Having troubles properly simulating a rectifier in ADS
The high frequency part of the circuit have to be developed keeping the wiring between components as short as possible. I'm referring to C3, C4, anode of DIODE1 and DIODE3, cathode of DIODE2 and...

18th July 2018, 11:56
Thread: Current in series resonant circuit
by albbg Replies
 11
 Views
 1,159
Closed: Re: Current in series resonant circuit
I think the reson is that you used a time step too large. Try with something like 1us

17th July 2018, 20:48
 Replies
 13
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 1,312
Closed: Re: No amplificaiton observed when THS3091 op amp used on THS3095 Evaluation Board
Did you properly drive the powerdown signal, present only in THS3095 amplifier (pin 8) ?

11th July 2018, 12:04
 Replies
 2
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 623
[SOLVED]Closed: Re: Specify component values for a given gain at a given frequency
Part a is correct in boh image 1 and image 2.
About part B, as suggested, just substitute s=jw and solve for the required gain (1 linear for the first circuit and 20dB for the second)
What is... 
5th June 2018, 21:10
 Replies
 11
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 1,191
Closed: Re: Weird phenomenon when measuring the P1dB of a LNA
What you observed is due to the self biasing of the transistor. Increasing the quiescent current the phenomenon should disappear.

23rd May 2018, 20:51
Thread: Applying KVL on an NPN BJT.
by albbg Replies
 4
 Views
 982
Closed: Re: Applying KVL on an NPN BJT.
Just place the voltage arrows across each element to see the equation
Vee + Ib*Rb + Vbe + IeRe = 0
is wrong. Doesn't matter the numerical value of voltage and current. The result is symbolic...
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