Register Blogs FAQ Members List Today's Posts Search Today's Posts Mark Forums Read

 General Electronics Chat Discussion forum for general chat about anything electronics related, including asking questions about material in the All About Circuits E-book, Worksheets, and Videos.

#1
07-09-2008, 09:16 AM
 studiot E-book Developer Join Date: Nov 2007 Location: Somerset UK Posts: 3,959

It has occurred to me that a thread where posters could pass on useful tips, tricks, rules-of-thumb, and conventions that may be of use for when you need a 'how to answer' not an in depth understanding. Please don't use this thread for asking questions.

I will kick off with a very simple but useful formula for making a non standard resistor by adding a parallel resistor to a standard one.

$R_{1} = \frac{R_{2}R_{d}}{R_{2} - R_{d}}$

$R_{1}$ is the required shunt resistor

$R_{d}$ is the desired non preferred value

$R_{2}$ is the (next) higher preferred value

Last edited by Dave; 07-09-2008 at 11:02 PM.
 The Following 2 Users Say Thank You to studiot For This Useful Post: nepdeep (11-13-2012), Niharika narayan (05-25-2012)
#2
07-09-2008, 09:50 PM
 SgtWookie Expert Member Join Date: Jul 2007 Location: In the vast midwest of the USA; CST Posts: 22,032

In retaliation for StudioT's post...

Attached files:
1) Series_ParallelResistanceCalculator.zip - contains an Excel spreadsheet that has StudioT's formula in it, and also does series of lookups on standard E6 thru E192 series resistance tables to ensure use of only the standard values in the results. Just put in the resistance you want where indicated, and resistor combinations for all E-series are displayed.
2) E24PLL.ZIP - contains E24PLL.TXT, a rather large (224kb) text file that you can scroll through to find pairs of resistors to use in parallel to obtain a particular resistance.

Here's a handy web page that does both series and parallel calculations for you, for E12 and E24 series resistors:
http://www.qsl.net/in3otd/parallr.html
Note that you must select E12 or E24 each time you enter a new value, or you will receive an error message.

[eta]
3) CapSMTMarkings is an excerpt from a KEMET Packaging and Marking document, for identification of SMT capacitor values.
If there are two letters and a number, the manufacturer is the first letter. If just a letter and a number, only the value and multiplier is specified.

Attached Images
 CapSMTMarkings.PNG (78.7 KB, 1254 views)
Attached Files
 Series_ParallelResistanceCalculator.zip (8.7 KB, 860 views) E24PLL.zip (64.6 KB, 637 views)
__________________
General info:
If you have a question, please start a thread/topic. I do not provide gratis assistance via PM nor E-mail, as that would violate the intent of this Board, which is sharing knowledge ... and deprives you of other knowledgeable input.

Last edited by bertus; 02-08-2014 at 03:38 PM. Reason: showing image full size
 The Following 9 Users Say Thank You to SgtWookie For This Useful Post: ahillelt (06-08-2013), Anal0g1nBlack (01-26-2011), Denesius (02-12-2014), mwmorgan (05-07-2013), nepdeep (11-13-2012), Niharika narayan (05-25-2012), PackratKing (08-16-2010), PGB1 (02-01-2013), Zanac-X (06-27-2012)
#3
07-10-2008, 05:07 AM
 thingmaker3 Super Moderator Join Date: May 2005 Location: Rural, Oregon GMT -8 Posts: 5,072 Blog Entries: 6

Rule of thumb for calculating power supply filter capacitors:

C = 0.7(I)/ΔE(f)

Where I = load current, ΔE = acceptable ripple voltage, and f = pulses per second from the rectifier.

For full wave rectified 60Hz, this works out to:
C = 0.00583 * I / ΔE
__________________
"I want to establish in your mind very clearly that you must not think I deny all that I do not admit. On the contrary, I think there are many things which may be true, and which I shall receive as such hereafter, though I do not as yet receive them; but that is not because there is any proof to the contrary, but that the proof in the affirmative is not yet sufficient for me"
 The Following User Says Thank You to thingmaker3 For This Useful Post: PackratKing (03-11-2013)
#4
07-10-2008, 07:46 AM
 miconos New Member Join Date: Jun 2008 Posts: 2
RFIC inductance calculation

Rule of thumb for RFIC inductance calculation:
1mm ~ 1nH
 The Following 2 Users Say Thank You to miconos For This Useful Post: nepdeep (11-13-2012), PGB1 (02-01-2013)
#5
08-16-2008, 12:09 AM
 yubyub Junior Member Join Date: Aug 2008 Posts: 19

Tip: check things more than once when soldering a big project. (i just soldered 50 transistors backwards)
 The Following 4 Users Say Thank You to yubyub For This Useful Post: gisdude (02-22-2014), nepdeep (11-13-2012), richiechen (01-12-2012), vishnu.mec (04-09-2012)
#6
11-04-2008, 07:36 PM
 KL7AJ E-book Developer Join Date: Nov 2008 Location: North Pole, Alaska Posts: 1,540

If any of you can get a copy of the November 2008 QST, I have an article in Technical Correspondence called "Making the Glass Half Full." I discuss in detail the reciprocal impedance parameters: conductance, susceptance, and admittance. These GREATLY simplify otherwise daunting parallel impedance problems.

73,

Eric
__________________
REAL men don't need voltmeters.
 The Following User Says Thank You to KL7AJ For This Useful Post: pabonbd71 (10-29-2012)
#7
12-18-2008, 01:15 PM
 eblc1388 Senior Member Join Date: Nov 2008 Location: UK Posts: 1,542

If your 9V battery connection is too short for the power supply, why not try the following and kill your project.

You won't need to power it up anymore.
Attached Images
 9VBat.jpg (42.0 KB, 1817 views)
__________________
L.Chung

Last edited by bertus; 07-13-2014 at 07:41 AM. Reason: showing image full size
#8
01-14-2009, 12:47 AM
 electratech Junior Member Join Date: Jan 2009 Location: Massillon, OH. Posts: 21
VIP chart

VIP chart for quick guide

Attached Images
 E-VIP chart.gif (7.5 KB, 1923 views)

Last edited by bertus; 02-08-2014 at 03:35 PM. Reason: showing image full size
 The Following 7 Users Say Thank You to electratech For This Useful Post: 1Mperios (12-11-2013), ElectroDFW (10-04-2011), Manticorp (11-13-2012), netwillie (08-29-2010), PackratKing (08-16-2010), RJ2 (08-11-2010), wayne2056 (03-09-2011)
#9
01-30-2009, 03:09 PM
 Skeebopstop Senior Member Join Date: Jan 2009 Location: Melbourne Posts: 358

Remember the skin effect. When trying to rid yourself of EMI, don't try to run it out of your system on a regular wire, rather ensure the wire has a large surface area (i.e. shielding).
#10
01-30-2009, 06:32 PM
 leftyretro Senior Member Join Date: Nov 2008 Location: Hercules, Ca. (SF Bay Area) Posts: 394

When designing power supplies be sure to size the input protection fuse so that the equipment being power blows up first so as to protect the power supply fuse from blowing open first.

Lefty
__________________
Measurement changes behaviour
 The Following User Says Thank You to leftyretro For This Useful Post: gisdude (02-22-2014)

 Tags 555, circuit, electronics, simulation, software, thread, tips, tricks

 Related Site Pages Section Title Worksheet Trigonometry for AC circuits Worksheet Capacitors Textbook How voltage, current, and resistance relate : Ohm's Law

 Similar Threads Thread Thread Starter Forum Replies Last Post tdavis.unk General Electronics Chat 1 02-05-2006 01:36 AM

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is Off Forum Rules
 Forum Jump User Control Panel Private Messages Subscriptions Who's Online Search Forums Forums Home Electronics Forums     General Electronics Chat     The Projects Forum     Homework Help     Electronics Resources Software, Microcomputing, and Communications Forums     Programmer's Corner     Embedded Systems and Microcontrollers     Computing and Networks     Radio and Communications Circuits and Projects     The Completed Projects Collection Abstract Forums     Math     Physics     General Science All About Circuits Commmunity Forums     Off-Topic     The Flea Market     Feedback and Suggestions

All times are GMT. The time now is 09:49 AM.