Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

amplify 3.5 volt to 5 volt

Status
Not open for further replies.

agmechatronics

New Member
hi every body
i have an analog signal from a sensor it is varying between 2.5 volt to 3.5 volt and i want to amplify it to (zero volt and 5 volt)
what is your suggestions
thank you
 
There are a lot of factors to consider, but I think the simplest solution would basically boil down to an op amp in a non-inverting configuration with a fixed gain. If you need higher current, you may need to add a buffer in front of it.

Also keep in mind that if you run an op-amp on a regular 5V supply, it will not swing all the way to 5V, but will come pretty close depending on what you use. If this is just an amplifier for an ADC or something like that, this may be acceptable. If you absolutely need the voltage to swing all the way to 0 and 5 volts and not just as far as the op amp will swing for a 5V supply, you may need a positive supply rail higher than 5V.

What is the application?
 
Last edited:
Welcome to ETO!
You can use an op-amp configured as a non-inverting one with a gain of 5 and an off-set of -2V. The op-amp will, however, need a supply voltage greater than +5V. It may also need a negative supply voltage if you want exactly 0V at the output.

Edit: JLNY beat me to it!
 
There are a lot of factors to consider, but I think the simplest solution would basically boil down to an op amp in a non-inverting configuration with a fixed gain. If you need higher current, you may need to add a buffer in front of it.

Also keep in mind that if you run an op-amp on a regular 5V supply, it will not swing all the way to 5V, but will come pretty close depending on what you use. If this is just an amplifier for an ADC or something like that, this may be acceptable. If you absolutely need the voltage to swing all the way to 0 and 5 volts and not just as far as the op amp will swing for a 5V supply, you may need a positive supply rail higher than 5V.

What is the application?
 
ok
the application a laser stop device it consist of a laser source and photo-diode sensor to receive the beam of laser then to a micro controller and when i cut the beam an indication led is turn on the problem is the beam is cut by a very small thin string about 0.1 mm and this give a very small signal its not noticed as i cut the beam with my hand or with an wire about 1 mm
so i need to amplify the signal
 
thank you alec_t
is this what you mean
Capture.JPG
Capture1.JPG
 
hi ag,
How quickly does the string cut/block the laser beam.
Is the 2.5 volt to 3.5 volt pulse or a level signal.
E
 
hi every body
i have an analog signal from a sensor it is varying between 2.5 volt to 3.5 volt and i want to amplify it to (zero volt and 5 volt)
what is your suggestions
thank you

Start reading at post#68 in this forum thread. A bit simpler than your post #6.

Gain = (5-0)/(3.5-2.5) = 5
Gain of a non-inverting amplifier = 1+R2/R1, so R2/R1=4

Pick R1 = 10K, therefore R2=40K

Middle of V(in) input range = (2.5+3.5)/2 = 3V
Middle of V(out) output range = (5+0)/2 = 2.5V
(V(ref)-V(in))/R1 = (V(in)-V(out))/R2

Subst, and rearrange, V(ref) = (R1/R2)*(V(in)-V(out)) + V(in) = (10K/40K)*(3-2.5) + 3 = 3.125

34a.png
 
Last edited:
You detect the AC not the DC.
Good idea. You could have an AC gain much higher than the gain of 5 in my post above... If you block DC, then the amplifier adjusts itself (slowly) for ambient light changes.
 
Good idea. You could have an AC gain much higher than the gain of 5 in my post above... If you block DC, then the amplifier adjusts itself (slowly) for ambient light changes.

This is why I asked the OP ref the laser beam 'blocking' speed, an AC coupled amplifier could be a better solution.

Another option would be DC amplifier/slicer with a limited auto ambient light correction.

The OP has not said how the amplified signal is going to be used.?
I am assuming just a pulse detection circuit.?

E
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top