nabhatti Posted March 7, 2005 Report Share Posted March 7, 2005 respected sir/madamif i am willing to do a certain project from this website, will i be able to get additional information relating to that project.thank youNaveed A. Bhatti713-410-6185 Quote Link to comment Share on other sites More sharing options...
audioguru Posted March 7, 2005 Report Share Posted March 7, 2005 Hi Naveed,Welcome to our forum. We'll be glad to help you! Quote Link to comment Share on other sites More sharing options...
nabhatti Posted March 8, 2005 Author Report Share Posted March 8, 2005 thank you very much for your reply.i was looking at the dancing leds topic in the section of motor, light and power control. in the schematic, i can see that IC1B is being powered up by B1 by connecting it to pin #8 but also pin # 4 is grounded. as far as i understand , if one of the powering voltage is + 15 the other one has to be negative of the same value. or is that pin something else other than the powering of amplifier. also IC1A is not being powered up at all. one more thing. could you please explain little bit at what point the circuit is doing what . thank you Quote Link to comment Share on other sites More sharing options...
audioguru Posted March 8, 2005 Report Share Posted March 8, 2005 Hi Naveed,The Dancing Lights project is here (copy-shortcut on its link):http://www.electronics-lab.com/projects/motor_light/021/index.html1) IC1A and IC1B are both inside the LM358 dual opamp so they are both powered by its pins 8 and 4.2) The LM358 is a single-supply opamp that doesn't need a negative supply like some other opamps. Unlike other opamps that need positive and negative 15V supplies, it can operate with a single supply as low as 3V, so the 9V battery in this project powers it fine. Find its datasheet on Google and study it. 3) The circuit description in the project clearly explains the operation of its parts. Is there anything about its circuit that you don't understand? ;D Quote Link to comment Share on other sites More sharing options...
nabhatti Posted March 9, 2005 Author Report Share Posted March 9, 2005 thank you very much for your replyi have one more quick questionif i need to use another op amp, which needs both negative and positive voltage to power it up , can i do thatfor example 741 op ampif i have more questions i will ask youthank you Quote Link to comment Share on other sites More sharing options...
audioguru Posted March 9, 2005 Report Share Posted March 9, 2005 if i need to use another op amp, which needs both negative and positive voltage to power it up , can i do that for example 741 op ampSure you can, then its negative output voltage or the entire positive and negative supplies across the 4017 IC will blow up the poor 4017! ;D ;D Quote Link to comment Share on other sites More sharing options...
nabhatti Posted March 9, 2005 Author Report Share Posted March 9, 2005 so that means i have no other choice other than using the LM 358 dual low power supply op amp. or do i have an alternative. also if i need to buy that LM 358 op amp. where can i purchase it .thank you Quote Link to comment Share on other sites More sharing options...
audioguru Posted March 10, 2005 Report Share Posted March 10, 2005 There are many single-supply, low-voltage-supply opamps. I don't know where you are or what you can get.What about an LM324? It is a popular quad opamp (4 opamps in one package) and is exactly the same as an LM358. Of course its package is bigger with more pins (14) and the pin numbers are different. ;D Quote Link to comment Share on other sites More sharing options...
MP Posted March 10, 2005 Report Share Posted March 10, 2005 An op amp needs both positive and negative supply voltage if the output is to go both positive and negative in response to a positive and negative input signal. If you do not have LM324:You can use the bipolar op-amps with a single supply if you use 1/2 VCC for the bias voltage. If you use only a single supply, your output will be shifted up in potential so that the minimum output is at ground instead of a negative voltage. There is nothing wrong with using an opamp on a single supply, but you probably won't want to do this if you need an output signal that swings from + to - with a zero level at ground. In this arrangement, you will not be able to sample negative voltage swings, but only positive ones.This is how you can use a 741 on a single supply. However, an advantage that the LM324 has over the 741 or similar types is RF immunity, low bandwidth, and relatively high CMRR. As audioguru has suggested it is your best way to go.MP Quote Link to comment Share on other sites More sharing options...
nabhatti Posted March 10, 2005 Author Report Share Posted March 10, 2005 im presently residing in houston tx. could you please let me know from where to purchase these op amps. Quote Link to comment Share on other sites More sharing options...
audioguru Posted March 10, 2005 Report Share Posted March 10, 2005 www.newarkinone.comwww.digikey.com Quote Link to comment Share on other sites More sharing options...
nabhatti Posted March 12, 2005 Author Report Share Posted March 12, 2005 i was looking at the circuit last night and i have a few questions for youas far as i understand, IC1A takes as input music or speech signal and amplifies it 100 times. i understand that the output of the op amp is synchronous with the input, that is for a certain frequency , whatever the voltage is at the input, the output will have 100 times that voltae. now my question is that after amplifying the signal, what does the decade counter does. does it light up each LED for a certain frequency or for every frequency all the LED's light up.please provide any kind of help possible.thank you Quote Link to comment Share on other sites More sharing options...
nabhatti Posted March 12, 2005 Author Report Share Posted March 12, 2005 i went to the website to purchase the op amp but there are so many of them e.g, LM358AM, LM358P etc. which one best suites this project. thank you Quote Link to comment Share on other sites More sharing options...
audioguru Posted March 12, 2005 Report Share Posted March 12, 2005 Hi Nab,Use www.google.com to find out what things are. When you enter CD4017 or LM358 you will get a list of links and a few will be manufacturers' info pages and datasheets. The ICs are available in different package sizes and different temperature ranges which are determined by the letters following their part number. On the info page, click on each listing to see its package size. Usually you want P or N. You don't need A or B extreme temperature ranges used by the military, but C is fine. All 4017 ICs have a B in their part number. The info page and datasheet for the 4017 describes it as a decade counter with 1 of 10 outputs. Then the datasheet shows that it produces one output at a time, and changes the output each time there is an input that has enough amplitude. The outputs sequence from 1 to 10 and then repeat for each loud sound of any frequency.If you are playing music with a loud bass beat, if its microphone is at the right distance from a speaker, it will light an LED for each beat, one LED after the other in sequence. If an orchestra is playing, the sequencing will be so fast it will appear like all LEDs are lighted dimly. If the music becomes extremely loud or not very loud, it will stop the sequencing with a single LED lighted until the sound becomes normal volume again. If you speak, it will step its outputs in sequence for each word or syllable if you speak at the right volume.If you want a circuit to light LEDs when certain frequencies are produced, like some for bass, others for mid-range and others for high frequencies then you need a different circuit called a Colour Organ. I think there are a few projects in our projects section. Quote Link to comment Share on other sites More sharing options...
MP Posted March 13, 2005 Report Share Posted March 13, 2005 They are the many package types that the manufacturer offers for these chips. Sometimes it is easy to get lost. If you are only concerned with the through hole DIP package, the P or PDIP designation is the standard package.MP Quote Link to comment Share on other sites More sharing options...
nabhatti Posted March 16, 2005 Author Report Share Posted March 16, 2005 since im using this circuit inside an electronics lab, im going to use 741 op amp powerig it up with 15 volts and powering the counter with 9 v . i also tested my circuit in pspice and it amplified the input signal 100 times at the output. now i tested the circuit again by removing R1 , R2 and C5 and i still got 100 times amplification . so whats the main purpose of R1 , R2 and C5 thank you Quote Link to comment Share on other sites More sharing options...
nabhatti Posted March 16, 2005 Author Report Share Posted March 16, 2005 im looking at cd4017be for the decade counter.is that going to be good for this projectthank you Quote Link to comment Share on other sites More sharing options...
audioguru Posted March 16, 2005 Report Share Posted March 16, 2005 Hi Nab,1) The absolute maximum input voltage of the counter is its supply voltage. If you power the 741 opamp from +15V then its output voltage will swing up to about +14V and feed about +13.4V through D1 to pin 14 of the counter, damaging it.2) The project is designed for an opamp like the LM358 that can operate with its input voltage equal to its negative supply (through R6). A 741 opamp cannot do that.3) The project is designed for an electret microphone that is powered by R1.4) The project is designed for IC1A to be powered by a single supply voltage. Its input is biased to 1/2 of the supply voltage by R2 and R3. Your spice simulator must be assuming that you are powering it with positive and negative supplies, where R2 isn't needed.5) The project is designed to be powered with a 9V battery whose internal resistance increases as it runs down. C5 is required to filter the battery's voltage so that it doesn't bounce all over the place. Your simulator must be assuming that the opamp is powered by a filtered, regulated supply, where C5 isn't needed.A CD4017BE is good for this project. Quote Link to comment Share on other sites More sharing options...
nabhatti Posted March 22, 2005 Author Report Share Posted March 22, 2005 i just have a few things to clearify.the gain mentioned in the project ( dancing led's ) is 100. i am assuming the gain mentioned is the maximum gain.and also is it a voltage gain or a signal gain ? im assuming its a voltage gainthank you Quote Link to comment Share on other sites More sharing options...
audioguru Posted March 22, 2005 Report Share Posted March 22, 2005 Hi Nab,The voltage gain of IC1A is exactly 101. It is not adjustable so there is no minimum or maximum. The signal gain in decibels is slightly more than 40dB. Quote Link to comment Share on other sites More sharing options...
nabhatti Posted April 3, 2005 Author Report Share Posted April 3, 2005 in the project (dancing LED's) , C5 is 25V electrolytic capacitor. what does that 25V specify.also , if i use a 100uF 50V electrolytic capacitor instead of 100uF 25V electrolytic capacitor, will that be ok to use. thank you. Quote Link to comment Share on other sites More sharing options...
nabhatti Posted April 5, 2005 Author Report Share Posted April 5, 2005 i builded the circuit and everything but when i tested it, i didnt work. no matter how high the volume is ( or low) the LED's wont move. also i changed the distance of the microphone from the radio but still same results. i then tested the circuit with a square wave having 0.1 [v] ampliude and then the LED's start moving 1 by 1 whenever the wave goes from low amplitude to high amplitude. could you please let me know what is going wrong.thank you Quote Link to comment Share on other sites More sharing options...
nabhatti Posted April 5, 2005 Author Report Share Posted April 5, 2005 could you please let me know from where to buy the electret microphone.again, im living in Houston,TX.thank you Quote Link to comment Share on other sites More sharing options...
audioguru Posted April 6, 2005 Report Share Posted April 6, 2005 Hi Nab,This mic should be available in Houston: Quote Link to comment Share on other sites More sharing options...
nabhatti Posted April 6, 2005 Author Report Share Posted April 6, 2005 i wish to extend the circuit but can not understand where to connect the terminals of the extented circuit. could you please let me know.once again , my project is Dancing LED's Quote Link to comment Share on other sites More sharing options...
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