Using any calculator that has M+, M-, and Mrc, calculate the value of two parallel resistors by following these steps: 1 divided by the value of the first resistor M+; 1 divided by the value of the second resistor M+; 1 divided by Mrc =the paralleled value.
Do not clear any entries; just press buttons in the sequence above. And do not forget to press the 'equals' symbol' at the end. And memory must be cleared before you begin (make sure the m symbol is not in the display when you begin).
More useful is the reverse. If you want two paralleled resistors to equal a certain value, follow these steps: 1 divided by the desired parallel value M+; 1 divided by a known/available resistor M-; 1 divided by Mrc = the value required.
An example: what value do you parallel with a 1200 to end up with 750?: 1 divided by 750 M+ (display shows .00133 with an m in the upper left); 1 divided by 1200 M- (screen shows .000833 after pressing M-); 1 divided by Mrc (screen shows .0005) ; hit equal button and you get 2000.
I have a POS calculator on my workbench and hitting these buttons has become second nature for me.
Do not clear any entries; just press buttons in the sequence above. And do not forget to press the 'equals' symbol' at the end. And memory must be cleared before you begin (make sure the m symbol is not in the display when you begin).
More useful is the reverse. If you want two paralleled resistors to equal a certain value, follow these steps: 1 divided by the desired parallel value M+; 1 divided by a known/available resistor M-; 1 divided by Mrc = the value required.
An example: what value do you parallel with a 1200 to end up with 750?: 1 divided by 750 M+ (display shows .00133 with an m in the upper left); 1 divided by 1200 M- (screen shows .000833 after pressing M-); 1 divided by Mrc (screen shows .0005) ; hit equal button and you get 2000.
I have a POS calculator on my workbench and hitting these buttons has become second nature for me.
My Casio fx-6000G has a reciprocal key '1/x' which places a superscript '-1' in the formula so to do resistance P || R you'd just enter:
P '1/x' '+' Q '1/x' '=' '1/x' '='
which is very nice. If you want calculate X where X || Y = Z and you know Y and Z:
Z '1/x' '-' Y '1/x' '=' '1/x' '='
My phone's calc app, RealCalc, alas has 1/x as a shift function, making this sequence tediously longer. I never thought
to use the memory though on this, it might be best.
P '1/x' '+' Q '1/x' '=' '1/x' '='
which is very nice. If you want calculate X where X || Y = Z and you know Y and Z:
Z '1/x' '-' Y '1/x' '=' '1/x' '='
My phone's calc app, RealCalc, alas has 1/x as a shift function, making this sequence tediously longer. I never thought
to use the memory though on this, it might be best.
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> calculator that has M+, M-, and Mrc
If a TI-30Xa has those buttons, I can't find them in dim light.
The 1/x key is right there. I would not have a desk calc without my 1/x and LOG.
Ah... my phone's calc has a 1/x which seems to work wrongly.
Win7 calc seems to lack 1/x on "Scientific", but has it on Standard.
If a TI-30Xa has those buttons, I can't find them in dim light.
The 1/x key is right there. I would not have a desk calc without my 1/x and LOG.
Ah... my phone's calc has a 1/x which seems to work wrongly.
Win7 calc seems to lack 1/x on "Scientific", but has it on Standard.
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