I need to build a circuit that will take 0-5 VDC input, multiply it by 2, add 10, and provide that value as the output VDC. I plan on using this with an air-fuel ratio measuring unit that I have. It provides the 0-5 VDC and I want to scale that to use with a automotive digital voltmeter that fits in the dashboard. Thanks.
You are correct about the 20V full scale. I won't have a 20V power supply available, nor do I want to get into anything exotic or expensive to build. I have no idea how easily such a task might be accomplished, but it sounds like it wouldn't be very practical.
Would it be any easier to build a circuit if all I'm looking for is to take the input 0-5VDC and double it for the output? That would be a compromise I could accept as the reading on the voltmeter would only be off by a consistent 10 volts, i.e. 2.2 VDC input would read 4.4 on the output, meaning an air-fuel ratio of 14.4.
If you could get into the voltmeter and force the tens digit to a "1", then you could get by with a gain of 2 (0-10V). You probably don't have enough experience to do this.
The problem is that he wants to read out fuel-air ratio which requires a 10V offset and a gain of two. That can't be achieved solely by changing the internal voltmeter sensitivity.
The problem is that he wants to read out fuel-air ratio which requires a 10V offset and a gain of two. That can't be achieved solely by changing the internal voltmeter sensitivity.
If he could scale the meter to 0-5V on the internal attenuator (most digital voltmeter modules are 0-200mV without the attenuator), and force the tens digit to "1", he wouldn't need any gain, offset, or higher voltage supply.
I need to build a circuit that will take 0-5 VDC input, multiply it by 2, add 10, and provide that value as the output VDC. I plan on using this with an air-fuel ratio measuring unit that I have. It provides the 0-5 VDC and I want to scale that to use with a automotive digital voltmeter that fits in the dashboard. Thanks.
This is not a difficult circuit to build! You described a linear system.
Your output equation is simply:
Vout=[2Vin+10] volts, where Vin=0-5 Vdc
Dagwood a 24 volt or higher IC DC-DC converter could be used for your V+ inputs to (dual or quad) single supply (24 volt or higher), rail to rail op-amp circuits. Your 0-5 volt input would be feed to an inverting amp (gain=2) with this output feed to an inverting summing amp (gain=10), the output:
Vout=2Vin+10 volts
You may or may not, depending on the sensor and digital volt meter specs need to design an appropriate interface between your designed circuit and these input/output devices-for proper loading, buffer etc?
Some suppliers give free samples ( ex. microchip ), I recieved 5 free 22 uH inductors for a dc-dc converter, just by asking and without ordering anything. Though the prices for the dc-dc converter and op-amp IC along with any support components needed for this project are reasonable.