All About Circuits Forum Help with clipping circuit
 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
03-20-2012, 06:01 PM
 ronaldocavalcante New Member Join Date: Mar 2012 Posts: 5
Help with clipping circuit

Hi, all. I'm from Bahia-Brasil and this is my first post.

Please, I need help to calculate currents across two ideal diodes D1 (direct) and D2 (reverse) on clipping circuit: (see circuit)

Main source: Vs = 7.5 peak (symmetrical triangle wave) with resistor (series) of 5.6 kohm

Diode D1 with DC source +3.25 V on katode
Diode D2 with DC source -3 V on anode
RL = 5.6 Kohm

I used electronics Workbench but the currents was wrong.

thanks for help

ronaldo
Attached Images
 clipping.jpg (16.7 KB, 25 views)
#2
03-20-2012, 08:30 PM
 bertus Administrator Join Date: Apr 2008 Location: Amsterdam,Holland (GMT + 1) Posts: 12,261

Hello,

Bertus
__________________
You don't have to know everything, if you know where to find it.
When you do ask questions, you may look stupid.
When you do NOT ask questions, you will STAY stupid.

It would be nice to have the Timezone ( GMT +/- x ) in the location field in the profile.
(User CP -> Edit Your Details)
 The Following User Says Thank You to bertus For This Useful Post: ronaldocavalcante (03-20-2012)
#3
03-21-2012, 02:16 PM
 ronaldocavalcante New Member Join Date: Mar 2012 Posts: 5

Hi, Bertus

I read the site and can't find the currents across D1 e D2, yet.

The V-out is OK, but the currents is always wrong.

ronaldo
#4
03-21-2012, 04:38 PM
 Ron H E-book Developer Join Date: Apr 2005 Location: Idaho, USA (GMT-7) Posts: 7,050

Are both resistors 5.6kΩ?
This looks like homework to me. We don't give answers to homework.
#5
03-21-2012, 11:58 PM
 ronaldocavalcante New Member Join Date: Mar 2012 Posts: 5

Yes, both are 5.6K.

I don't want the result! I'd like a hint to help me solve the question.

The Vout is simple: V1 and V2 (positive and negative) + 0,7V (diode). In this case (ideal diode) level of the clipping voltage, V1 and V2.

But to determine currents I tried thevenin and superposition without success.

Steps: open V2, short in V1 determines Vo1 and IR1a using Vin

Open V1, short in V2 determines Vo2 and IR1b using V1.

Vo = Vo1+Vo2 and IR1=IR1a+IR1b.

When I use the simulation (EWB) Vo is OK and currents not.

I repeat that not need results, but help the way to try solve the problem.

regards

ronaldo
#6
03-22-2012, 03:56 AM
 ronaldocavalcante New Member Join Date: Mar 2012 Posts: 5

Ok.
Tomorrow I'll make this experience. I've got a scope 60MHz and 2 true rms multimeter.

As I don't have a function generator, I'll try find here a triangle wave oscilator circuit.

Maybe my calculation error is found.

thanks

Last edited by ronaldocavalcante; 03-22-2012 at 04:04 AM.
#7
03-22-2012, 02:44 PM
 Ron H E-book Developer Join Date: Apr 2005 Location: Idaho, USA (GMT-7) Posts: 7,050

Convert Vs and the two resistors to the Thevenin equivalent. Then the solution will be simple.

Is Vs ±7.5V? You said 7.5V peak. I'm assuming that means 15V p-p.
#8
03-22-2012, 10:16 PM
 ronaldocavalcante New Member Join Date: Mar 2012 Posts: 5

Solved!!!

It was my problem. Caculation of decimals was wrong
Also, I forgot that the function generator of EWB generates the RMS and oscilloscope uses peak voltage.

thanks for all

ronaldo

 Tags circuit, clipping

 Related Site Pages Section Title Worksheet Precise diode circuits Textbook Other waveshapes : Mixed-frequency Ac Signals Textbook CMOS 555 LONG DURATION FLYBACK LED FLASHER : 555 Timer Circuits Textbook CMOS 555 LONG DURATION BLUE LED FLASHER : 555 Timer Circuits Textbook 555 HYSTERETIC OSCILLATOR : 555 Timer Circuits Textbook SPICE models : Diodes And Rectifiers Textbook Zener diodes : Diodes And Rectifiers Textbook Voltage multipliers : Diodes And Rectifiers Textbook Clipper circuits : Diodes And Rectifiers Textbook Peak detector : Diodes And Rectifiers

 Similar Threads Thread Thread Starter Forum Replies Last Post Ocelot The Projects Forum 4 07-16-2011 03:18 PM avskalai The Projects Forum 1 07-16-2011 03:45 AM smartweb The Projects Forum 18 07-01-2010 09:40 PM MoC General Electronics Chat 4 03-18-2010 12:33 PM Chris15 The Projects Forum 13 07-08-2009 09:32 PM

 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 05:30 AM.