203 Threads found on edaboard.com: Isolation And Resistor
Like I remember the resistor (in theory) suppose to be 100 omh, and you need it for improve isolation and return loss of the ports. if you need a formula tell me!!
RF, Microwave, Antennas and Optics :: 19.10.2006 09:30 :: DDavid :: Replies: 3 :: Views: 1031
This is a simple well resistor under STI (Field), the cross section shows an NWell resistor.
For better isolation the resistor could sit in another well (for a triple well process). It could also be surrounded by an isolation ring and could have a metal field plate over the top of the (...)
Analog IC Design and Layout :: 08.01.2011 11:20 :: Colbhaidh :: Replies: 2 :: Views: 899
hi in our design we've used a parallel RC circuit for Chassis ground and Digital ground isolation
the resistor value is 1M ohm and the capacitor is 1000pf_2KV
i was told that it's basically for "EMI ,EMC and ESD protection":?:
i would like to know why exactly it is used and how (...)
Professional Hardware and Electronics Design :: 16.06.2011 05:48 :: haridharan :: Replies: 1 :: Views: 1327
If you don't use resistors in Wilkinson divider, you don't have isolation between outputs. But VSWR and insertion loss does not change.
RF, Microwave, Antennas and Optics :: 07.08.2012 04:05 :: chapt :: Replies: 14 :: Views: 606
The datasheet you uploaded describes: "Splitters are used extensively in wireless signal distribution networks, to split the base station transmitted signal, Tx, into many different paths to reach multiple antennas, ...."
It is clear that what is being regarded in the datasheet is a power splitter to be used to feed power to an ante
RF, Microwave, Antennas and Optics :: 10.05.2003 13:12 :: nandopg :: Replies: 14 :: Views: 9570
I have saw a 6-finger mutiple line design ,it use a little cap shunt with the isolation term resistor to compensate.another problem:when I use ADS2002 to design such a coupler,the EM simulate results sames have much difference with schematic results ,so I think the 6-finger lange passive model ADS2002 use maybe not so exact.but how to do a calibrat
RF, Microwave, Antennas and Optics :: 21.06.2003 21:27 :: Needbias :: Replies: 2 :: Views: 952
If you need only to make a fact: is ringing voltage or not, use opto isolation and a capacitor to block dc voltage.
If you need to know what exactly voltage is, use AD on line side (powered from the line), then opto isolation use between AD and uC.
Professional Hardware and Electronics Design :: 09.03.2004 04:54 :: arturt134 :: Replies: 7 :: Views: 1317
You could try a Wilkinson type divider, and use coaxial cable for the 2 transmission lines. This is basically composed by 2 quarter wavelength 70.7 ohm transmission lines, which transform the impedance of 50 ohm at the terminations to 100 ohm.The 100 ohm resistor across improves the isolation and the output match. (...)
RF, Microwave, Antennas and Optics :: 05.03.2004 04:58 :: AL0117 :: Replies: 6 :: Views: 1838
Hi, trail. A PUN Diode switch is just a current controlled resistor. A simple design can be a shunt diode (one end to the ground) connected to a TX line. When forward biased, the switch acts as a short circuit, reflecting any RF signals entering either ends of the TX line.
It seems that you have poor isolation ( as you say you apply the s
RF, Microwave, Antennas and Optics :: 26.06.2004 08:27 :: lguancho :: Replies: 6 :: Views: 1562
anyone know how a series 18ohm resistor comes up for the isolation between VDD and the power supply? why not other value?
RF, Microwave, Antennas and Optics :: 13.01.2005 22:26 :: kyjackchan :: Replies: 5 :: Views: 1252
There are several drawbacks of having long(er than needed) lines.
1. Losses will increase
2. Exact phasing of the divider network is difficult in practice. As Flatulent poined, your bandwidth will narrow even in theory when you add extra multiples of quarter wavelength. However, in practice things are going to be even worse as exact elec
Electromagnetic Design and Simulation :: 11.02.2005 04:33 :: flyhigh :: Replies: 2 :: Views: 1011
The cbe structure will have a larger collector-substrate capacitance than the cbe structure. In addition, dependent on the design rules, the cbe structure will have slightly higher collector-base capacitance (Cbc) due to the collector and base electrode being minimum space from each other. In some double poly bipolar technologies, you will also g
Analog IC Design and Layout :: 17.04.2005 01:49 :: krashkealoha :: Replies: 2 :: Views: 749
I used Wilkinson 2-way splitter/combiner to combine PA power. The frequency is 900MHz. The port 2 power is 20W, and port 3 is also 20W, so port 1 is 40W. Normaly, the balance resistor (100Ω) is lossless and can provide good isolation between port 2 and port 3. But how to choose the power rating for the (...)
RF, Microwave, Antennas and Optics :: 24.05.2005 03:48 :: sunstar16 :: Replies: 2 :: Views: 652
In this case you will need to use a resistor of,say 100kΩ, to provide a reference between 0Vdc of the HV output and the housing (I assume that the MCU GND is identical with the potential of the housing).
Using resistors as a voltage divider divide the output voltage of 230Vdc to something that can be measured, say 5Vdc.
If the (...)
Analog Circuit Design :: 01.10.2005 00:10 :: IanP :: Replies: 14 :: Views: 2268
The trans may break from any phenomenon,so it is better (for safety) use high isolation DC/DC converter at output of transomer (regulated trans output),you can have double layer isolation,DC/DC have 3000VDC isolation and you can buy them easily.
You can use dc/dc for only the probe section of you circuit (probe side (...)
Microcontrollers :: 19.12.2005 13:42 :: 7rots51 :: Replies: 9 :: Views: 1727
If you dont worry about isolation, and you may consider 10:1 or similar isolation transformer, here is a simple circuit that will convert +230 to -230 to 5V-0V ..
You may feed the output directly to ADC pin or you may use a unity gain buffer (opamp) ..
Just add a 5.1V zener diode ..
This circuit has a small drawback: at 0V input the (...)
Electronic Elementary Questions :: 20.04.2006 22:31 :: IanP :: Replies: 1 :: Views: 2047
Sometimes putting a capacitor in parallel with the resistor greatly improves isolation.
Try using a 120ohm resistor so that the parallel cap brings it down closer to 100ohms.
The cap basically reduces the inductance of the resistor and reduces the phase delay through the resistor. (...)
RF, Microwave, Antennas and Optics :: 17.07.2006 10:06 :: xxargs :: Replies: 9 :: Views: 1967
It can serve as an isolation for high frequency noise since this O ohms are inductive in nature!
Professional Hardware and Electronics Design :: 17.08.2006 04:48 :: rommelm :: Replies: 11 :: Views: 2788
I don't understand why you installed the transorbs from each line to the chassis. I think you should have installed one from each line to ground. After all, you need protection from overvoltages between these lines. Then you can install something else from ground to chassis, like a single transorb that would give you the required isolation. Or
Professional Hardware and Electronics Design :: 01.09.2006 12:41 :: VVV :: Replies: 9 :: Views: 4089
I'm now designing a 5 stages 'cascade' Wilkinson power divider (bandwidth 0.5GHz -6.5 GHz) on RF-60A (Er=6.15, H=1.542mm)according to "A general design formula of multi-section power divider based on singly terminated filter design theory".
With the value I calculated according to the specifications in my case, I can have exactly the
RF, Microwave, Antennas and Optics :: 28.11.2006 03:48 :: alard :: Replies: 8 :: Views: 1648
hi, i am using corporate arrangement of wilkinson coupler to split an input power into 4 ports(Equal division) and 4 power amps are used each with an output of 2Watts.
My question is that the isolation resistors used need to be power resistors or ordinary resistors will serve the purpose,keeping in mind (...)
RF, Microwave, Antennas and Optics :: 05.09.2007 01:41 :: umarazad :: Replies: 10 :: Views: 1890
Is someone able to solve any doubt I have about the circuitry which must be set between the LAN PHY chip and the RJ45 connector?
I know it is necessary to set a transformer, and I guess it works as an isolation protector against voltage peak coming from the RJ45 connector, but actually I cannot explain some physical aspects of its (...)
Network :: 19.09.2007 04:27 :: McShamrock :: Replies: 2 :: Views: 913
One can apply even-odd mode analysis to understand the operation of Willkinson divider.
Even mode: the middle point of resistor is open circuit and resistor is not contained in the circuit, so the even part is indeed losless.
Odd mode: the middle point of resistor is short circuited so the (...)
RF, Microwave, Antennas and Optics :: 27.10.2007 14:42 :: flyhigh :: Replies: 7 :: Views: 1308
OD stands for the thin oxide region or active area.
STI stands for shallow trench isolation (opposite of OD)
In an OD NWELL resistor the resistor is formed in an active area. In the case of an STI NWELL resistor it is formed under the STI oxide.
The models for these two (...)
Analog IC Design and Layout :: 01.11.2007 21:11 :: DoctorProf :: Replies: 2 :: Views: 1731
Total isolation and in the same time dc leakage detection is not possible ..
Unfortunatelly, you need a common reference to monitor any leakages or shortcircuits ..
One method is to introduce a dc offset (say 10Vdc - now your 0V is 10V and 12V becomes 22V) through a high-ohm resistor (something like 10MΩ) (...)
Professional Hardware and Electronics Design :: 10.11.2007 21:19 :: IanP :: Replies: 2 :: Views: 1364
I am facing one problem in ADS momentum, i am designing Wilkinson power divider. i have done the lay out. and trying to tune it in 1 Ghz. but the problem is coming due the isolation reistor 100Ω, connected b/n the two o/p. i am confused abt the choosing the resistor. what kind of resistor should i choose ? thats why o/p (...)
RF, Microwave, Antennas and Optics :: 22.02.2008 23:47 :: ayan_ns :: Replies: 1 :: Views: 565
My first point is to consider, if the optocoupler connected circuit is actually directly exposed to ESD. That's not obvious to my opinion.
If this can't be avoided by design, it would be meaningful to determine the isolation breakdown voltage of the optocoupler with ESD. It's likely to be much higher than specified maximum ratings but possibly n
Professional Hardware and Electronics Design :: 06.09.2008 07:04 :: FvM :: Replies: 2 :: Views: 2791
I have used resistive dividers @ 3 GHz with no problem. Of course you get a losses compared to conventional wilkinson divider. But in case you do not mind burning half of the power in the divider resistors and you don't mind that the isolation between output ports is only 6 dBs, then resistive power divider is most simple solution (...)
RF, Microwave, Antennas and Optics :: 09.01.2009 14:18 :: karote :: Replies: 4 :: Views: 1446
Can anybody tell me how to choose the Power Rating of isolation resisters while designing Power Divider?
RF, Microwave, Antennas and Optics :: 17.01.2009 19:49 :: tshah :: Replies: 7 :: Views: 1031
Use transformer for best isolation and conversion of voltages to low rang and use ADC to measure your voltage.
but you need to make a lookup table for translating ADC values to voltages scaled from 240 to 5-10 volts by transformer.
Analog Circuit Design :: 25.06.2009 02:38 :: mfarooq1 :: Replies: 4 :: Views: 1045
If you have a known good spec, or better yet a 4-point
(Kelvin) measurement of the trace without power applied,
for trace resistance per length then you can use that and a
simple voltage difference reading to get your current
without having to cut and add a sense element. Though
PCB traces are meant to be pretty low resistance, so if you
Analog Circuit Design :: 07.11.2009 14:33 :: dick_freebird :: Replies: 9 :: Views: 4039
To Measure voltage :-
Just drop the voltage by using step down transformer. After that check whether isolation is needed. If yes than use Opto coupler for isolation.
To measure current :-
For Current there is three different technology
1. With Sense resistor
2. Current Transformer
3. Hall Effect Sensor.
Use any one & after (...)
Microcontrollers :: 05.02.2010 06:13 :: chanchal.chauhan :: Replies: 3 :: Views: 1675
I'll second Nandhu on the linear optocoupler suggestion. LOC110 is another linear optocoupler chip.
Consider also a different approach - put a separate A/D converter chip on the isolated side, run digital signals across the isolation barrier.
Microcontrollers :: 10.02.2010 14:29 :: kender :: Replies: 8 :: Views: 1613
Many audio opamps are wideband and therefore oscillate at a high frequency if they drive the fairly high capacitance of a shielded audio cable. A 100 ohm resistor from the output of the opamp circuit isolates the cable capacitance and prevents oscillation.
Inside a receiver there might not be shielded cable or its length is (...)
Hobby Circuits and Small Projects Problems :: 02.03.2010 15:43 :: Audioguru :: Replies: 8 :: Views: 2026
using a transformer or a gate driver are better solutions ,since it provide isolation, and reduce the stress for some components.
Power Electronics :: 18.03.2010 21:43 :: --jason-- :: Replies: 4 :: Views: 1179
Have looked at your design, but not your code.
The circuit is really wrong, R3 is at 10k so it will never turn on the optos led.
Your AC circuit is connected to the 0v of the Pic - so you do not have any isolation !
If you search on this string, as I have just done, you will find similar circuits in this forum that should show you h
Microcontrollers :: 24.03.2010 14:30 :: wp100 :: Replies: 7 :: Views: 2508
I want to isolate two voltage supplies that I have in spice, I mean I do not want to connect their negative side together( In experiment, easily I do not connect) but what about in spice? I want to use one of the voltage supplies as a floating volatage supply.
any idea will be appreciated,
Power Electronics :: 23.07.2010 16:36 :: elahetal :: Replies: 4 :: Views: 502
There is the problem with isolation. Enough power could leak from one transmitter to the other to damage the other receiver.
I would suggest not doing this.
RF, Microwave, Antennas and Optics :: 03.08.2010 12:45 :: flatulent :: Replies: 8 :: Views: 982
I am using 8051 for serial communication. It talks with another microcontroller at TTL level. So I think there is no need for MAX232. Am I correct ?. Is it enough if I connect tx of miconA to rx of moconB and rx miconA to tx of miconB. Is it like this or I need to connect some other way?. If I want to isolate this path, how can I do that?.
Embedded Systems and Real-Time OS :: 16.08.2010 04:55 :: vamanan :: Replies: 1 :: Views: 1786
Yes, an optocoupler would be a good way of providing isolation and doing the voltage level conversion.
Electronic Elementary Questions :: 19.01.2011 03:23 :: keith1200rs :: Replies: 15 :: Views: 1688
FIRST and FOREMOST - the circuit is connected directly to AC mains and is therefore potentially lethal to touch - make sure you respect that before going any further.
There are several ways to do what you want although most use a different method to fire the triac. In your case, you absolutely MUST isolate the control circuit (0 - 5V circuit) fro
Electronic Elementary Questions :: 12.03.2011 04:48 :: betwixt :: Replies: 2 :: Views: 850
I've done this a couple of times.
The line is normally 50vdc, either polarity and when the phone rings there is 75v ac on the line.
If you feed the line to a bridge rectifier and then to a voltage detector, when the voltage exceeds say 60v you can turn on the led in a opto isolator via a zener diode circuit to give you a ringing signal.
T o off
Hobby Circuits and Small Projects Problems :: 11.05.2011 01:03 :: dr pepper :: Replies: 1 :: Views: 870
Do you know where I can source high-voltage , low-power 1 MegOhm resistors for paralleling with Y caps, which bridge the primary ? to ? secondary isolation barrier in an offline SMPS?
These resistors must withstand the 3500VAC HiPot isolation tester.
-Though I cannot find (...)
Power Electronics :: 29.07.2011 05:58 :: grizedale :: Replies: 4 :: Views: 853
For opto isolation you can use IL3585. I use this IC for DMX
Professional Hardware and Electronics Design :: 05.09.2011 17:44 :: ZASto :: Replies: 12 :: Views: 1826
Yes you can do it this way, but in order to avoid any additional current dividers, why not to use a 40-50A sensor?
See for example:
Allegro | Products | ACS756 Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 3 kVRMS Voltage isolation and a Low-Resistance Cu
Analog Circuit Design :: 28.09.2011 03:07 :: mister_rf :: Replies: 4 :: Views: 653
I have a RS485 based relay control hardware. I need to transfer a ground signal to a remote component. Once the component is on (by receiving my ground signal), it sends a back indication in form of ground signal which is received at AT89C51. I have isolated the ground sent/received to/from the component using optocouplers. I need
Professional Hardware and Electronics Design :: 10.11.2011 23:53 :: makjee :: Replies: 8 :: Views: 814
1:what is the output of the pin7 of the hcpl-7840? how about the pin6? is it sinusoidal waveform?
Yes, if apply some sinusoidal waveform on the shunt resistor.
The HCPL-7840 consists of a sigma-delta analog-to-digital converter optically coupled to a digital-to-analog converter.
2:what is the output of the mc34082a whi
Analog Circuit Design :: 17.02.2012 12:20 :: mister_rf :: Replies: 2 :: Views: 354
Rogers 4350 material should work fine at least up to 10GHz.
To get good isolation at high frequencies must have the right terminating impedance at the other port (where you placed a 51 ohms resistor). The 50 ohms load resistor should have minimum parasitic inductance (preferable is to place 3 x 150 ohms SMD resistors in (...)
RF, Microwave, Antennas and Optics :: 01.03.2012 12:16 :: vfone :: Replies: 2 :: Views: 306
As you may know there is lots of info on the SEPIC topology on the web. I think best is to try to figure out how it functions (what are the voltages and currents in each component for your output requirements). When done, you have some idea of the components you require. the inductors will be the hardest ones. If you have specific proble
Power Electronics :: 13.03.2012 05:15 :: WimRFP :: Replies: 62 :: Views: 1441
The resistor / capacitor circuits are simply voltage dividing ; and can only be use (with a lot of care as there is no isolation) for low load current applications.
Isolated opamps are used for signal only (no power transfer) and use magnetic or optical isolation techniques
Analog Circuit Design :: 28.03.2012 03:27 :: klystron :: Replies: 10 :: Views: 1630