Hi Ramussons,Summing can be done with resistor networks IF the voltage is being monitored only by a DMM or an oscilloscope.
If the voltage is to be processed by another stage, the "loading" of that resistor divider network will have to be taken into account.
Use a 4 Flip Flop Shift register. This is for a 5 Volt Shift register.
View attachment 245355
I have not taken the voltage drops of the Diodes in calculating the resistor values.
If you "load" the output, voltages will reduce.
Hi Ian,With a page of algebra and three simultaneous equations you can eliminate the diodes.
Replace all the resistances with conductances, and apply Kirchhoff’s current law.
1). -4G1 + G2 + G3 + G4 = 0
2). 2G1 - 3G2 + 2G3 + 2G4 = 0
3). ½G1 + ½G2 - 4½G3 + ½G4 = 0
Eliminating G1 from the first two equations gives 2G1 = G2
substituting back in gives G2 = 4G3
substituting in 3) gives ¾G2 = G4
Turning back to resistances
R1= 2R2
R3 = 4R2
R4 = 4/3 R2
They work out to be 15k, 7.5k, 30k and 10k. Suspiciously all E24 values. Was this homework?
Hi Eric,hi Hai,
Resistor values modified.
Note: The Shift register may not output exactly 5V per step, it could be 4.8V
What are you driving with the output of the Summer.??
E
Yes, I know.With a page of algebra and three simultaneous equations you can eliminate the diodes.
Replace all the resistances with conductances, and apply Kirchhoff’s current law.
1). -4G1 + G2 + G3 + G4 = 0
2). 2G1 - 3G2 + 2G3 + 2G4 = 0
3). ½G1 + ½G2 - 4½G3 + ½G4 = 0
Eliminating G1 from the first two equations gives 2G1 = G2
substituting back in gives G2 = 4G3
substituting in 3) gives ¾G2 = G4
Turning back to resistances
R1= 2R2
R3 = 4R2
R4 = 4/3 R2
They work out to be 15k, 7.5k, 30k and 10k (or decades thereof). Suspiciously all E24 values. Was this homework?
There’s something really satisfying about a circuit which performs as predicted after a page or two of algebra. Much more so that one that works like its SPICE simulation.Yes, I know.
Was just a little lazy to do all that algebra
And I can imagine few things more tedious than solving a page or two of algebra equations.There’s something really satisfying about a circuit which performs as predicted after a page or two of algebra.
Hi Eric,hi Hai,
What is the load on the output of that circuit, what is it driving into.?
E
I have to admit I did it at work - where I was watching a battery charge!And I can imagine few things more tedious than solving a page or two of algebra equations.
Finally!! A genuine alternative to watch paint dry.I have to admit I did it at work - where I was watching a battery charge!
by Jake Hertz
by Jake Hertz