double the input voltage

[imgemini]

hi
i want to double the signal the is 10V into 20 v .any idea is non- inverting using 741 will work :?:

 

[Nigel Goodwin]

hi
i want to double the signal the is 10V into 20 v .any idea is non- inverting using 741 will work :?:

Depending what you are trying to do, an opamp with a non-inverting gain of 2 will do this.

But your question is too obscure, as you don't really give details it's hard to say if it would work for your application.

 

[imgemini]

i m working on noise genrator....giving output 10V i need 23V ...

so is there any way to make it double



any other think

can i use noise from radio .........just asking in there any differnce b/w noise genrator (noise ) and the noise coming from radio when its not tune into any station :!:

 

[Nigel Goodwin]

i m working on noise genrator....giving output 10V i need 23V ...

so is there any way to make it double

You've got two threads going on the same subject, yet you're posting totally contrary requests in them!.

Try posting EXACTLY! what you are wanting to do, I'm presuming (from above) that it's simply to amplify a white noise signal from 10V p-p to 23V p-p?. But you need to give far more details, such as what is is needed to do?, what is it feeding?, how much power is required?, what is the load impedance?, what power supplies do you have?.

In the other thread you've just replied that's you want a power supply to give 20V off a 10V supply, which I presume isn't at all what you need?.

any other think

can i use noise from radio .........just asking in there any differnce b/w noise genrator (noise ) and the noise coming from radio when its not tune into any station :!:

Yes, an FM radio off-station gives white noise, assuming you want white noise? - for audio use pink noise is more often required, and can be generated by filtering white noise.

 

[imgemini]

yes u got it

i am working on noise genrator circuit . post any noise circuit that u have can genrator 17V to 23V ....

or circuit in which i can use non-inverting 741 to get requied output 23voltage :?:



i m in problem man and i need answer fast that y i post two with same problem ..... i hope u will come up with working noise genrator circuit which can work with 741 to get 23v output

 

[Nigel Goodwin]

yes u got it

i am working on noise genrator circuit . post any noise circuit that u have can genrator 17V to 23V ....

or circuit in which i can use non-inverting 741 to get requied output 23voltage :?:



i m in problem man and i need answer fast that y i post two with same problem ..... i hope u will come up with working noise genrator circuit which can work with 741 to get 23v output

You still haven't given many details, try answering the previous questions I asked!. Also, for a new question, do you have some of the circuit already designed and built? - presumably so as you asked how to amplify the noise, rather than create it?.

 

[imgemini]

hi friend
this is it's a simple sawtooth generator ... that delivers a very small output 0.2v DC and i need to change it into 23V DC

1) will non-inverting amplifier circuits work for this?

2) if not then what will work here?

3) circuit requested if u have

 

[Styx]

0.2V upto 23V !!!!alot of noise will exist - but that is what you want.

What you want is an opamp that can run off a single supply. Most are dual +/-15V but some of them will allow you to run of a 30V single rail. Remember you supply voltage MUST be greater that the desired signal voltage

The OPA547T,LTC1150CN8,MAX472ESA will work at 30V

 

[imgemini]

i will be very great ful if u post the circuit ..

 

[imgemini]

here is the circuit i use with 741 op but show 3.05V as inout was 0.5V :roll:


so all of u r saying 741 will not work


then what should i do plesae coem up with any circuit will be great

 

[Nigel Goodwin]

here is the circuit i use with 741 op but show 3.05V as inout was 0.5V :roll:

What people are asking for is the circuit (schematic) diagram, not your board layout!.

But without drawing it out, I would be surprised if it only puts out 0.2V, I would expect a simple sawtooth oscillator like that to output a great deal more - probably approaching the supply rails!.

A 741 is an extremely old opamp, and far better ones are available, a 741 is always going to restrict the design.

 

[imgemini]

its MC1458
so u told me that sawtooth is AC not DC

can i mix my AC signal with DC voltage to get 23Voltage?

if yes who?........what will be behavier of the sawtooth signal?

 

[Styx]

hang on!!!

are you sa\ying you want a 23V Dc signal BUT you want some noise on it, so you trying to get a 0.2V pk-pk triangle wave and then give some DC offset so you end up with

Vtri + 23V

thus giving you the "apperance" of 0.2V worth of noise on your DC signal?

If this is the case the 0.2C pk-pk with a DC offset isn't really noise

 

[samcheetah]

or is it the other way round? :?

because 0.2V of noise (ripple) might be there in the first place if the project is powered from the wall socket.

i think he wants 23V of noise

 

[Styx]

or is it the other way round? :?

because 0.2V of noise (ripple) might be there in the first place if the project is powered from the wall socket.

i think he wants 23V of noise

23V pk-pk of noise? true it could be that.
But the whole point of these question is

We need some more infomation!.
What do you want this "noise" for. 23V is quite high a voltage (for a signal) - what is it feeding? why do you need a noisy signal for?

 

[Nigel Goodwin]

We need some more infomation!.
What do you want this "noise" for. 23V is quite high a voltage (for a signal) - what is it feeding? why do you need a noisy signal for?

Eventually he's supplied a little more information (in a PM, but I thought I'd post a reply here).

He's wanting to build a cellphone 'jammer', and wants a varying voltage (either random or sawtooth) from 0-23V - presumably for tuning on a varicap diode in an oscillator circuit?. It's also for the course he's on, so doing his work for him seems rather like cheating?, but a few suitable hints should set him on the way.

This bears no resemblance at all to any of his previous questions, which is why we weren't getting any where!.

Anyway, here's one simple solution to the problem:

Use a constant current source from a 24V (or so) power supply to charge a capacitor, the top end of the capacitor is the tuning voltage for the varicap.

Place an NPN transistor across the capacitor, collector to the top, and emitter to ground.

Feed the base of the transistor from a squarewave oscillator, a 555 would be suitable.

When the base of the transistor goes high it turns ON, discharging the capacitor, when it goes high the transistors turns OFF - allowing the capacitor to charge in a linear, giving a nice sawtooth ramp.

The constant current, capacitor value, frequency and mark space ratio of the oscillator, will all require calculating (or finding by experiment).

 

[imgemini]

what u think this will work

:?:

 

[Nigel Goodwin]

what u think this will work

:?:

No!.

Here's the relevent part of the circuit I just described!. T1 is the constant current generator.

 

[imgemini]

if will be great ful if u give me value,s of circuits R? C? and all other,s

 

[Nigel Goodwin]

if will be great ful if u give me value,s of circuits R? C? and all other,s

'YOU' need to work them out, based on your particular design choices, the operation of the circuit is pretty obvious - we're not here to do your assignments for you, although we don't mind offering suggestions :lol: