Flameproof resistors in series, is it okay to do?

[Jim Lazzaro]

I need a flameproof resistor of 1.2k ohms but I only have one of 1k
and one of 200 ohms.(both flameproof)
Now theoretically speaking, connecting them in series the total
resistance would be 1.2k ohms but would the safety factor of a
flameproof/fusable resistor still be effective?
Any comments please.
Thanks, Jim

 

[Jerry Greenberg]

Generaly, you can put resistors in series to obtain a higher value. If
you need a lower value you can put them in parallel. In parallel, the
formula is not a simple addition or subtraction. Take care for the
wattage ratings of the resistors.

Jerry G.
========

Jim_Lazzaro@hotmail.com (Jim Lazzaro) wrote in message news:<fae7122f.0406190745.5b660269@posting.google.com>...

I need a flameproof resistor of 1.2k ohms but I only have one of 1k
and one of 200 ohms.(both flameproof)
Now theoretically speaking, connecting them in series the total
resistance would be 1.2k ohms but would the safety factor of a
flameproof/fusable resistor still be effective?
Any comments please.
Thanks, Jim

 

[Phil Allison]

"Jim Lazzaro"

I need a flameproof resistor of 1.2k ohms but I only have one of 1k
and one of 200 ohms.(both flameproof)
Now theoretically speaking, connecting them in series the total
resistance would be 1.2k ohms but would the safety factor of a
flameproof/fusible resistor still be effective?

** A flameproof resistor will not go up in flames - end of story. A
fusible resistor may or may not have a specific fusing current, in any case
it is far from a precise value.

One of your resistors has 83 % of the desired value, so it will likely
go open very close to the same conditions as one with the full value.



.............. Phil

 

[Jim Lazzaro]

I wanted to be clear about the theoretical aspect on combining
flameproof/fusable resistors and now I am; Thanks for the input and
especially to Phill for the explanation.
Jim

"Phil Allison" <philallison@tpg.com.au> wrote in message news:<2jke9tF129neeU1@uni-berlin.de>...

"Jim Lazzaro"

I need a flameproof resistor of 1.2k ohms but I only have one of 1k
and one of 200 ohms.(both flameproof)
Now theoretically speaking, connecting them in series the total
resistance would be 1.2k ohms but would the safety factor of a
flameproof/fusible resistor still be effective?


** A flameproof resistor will not go up in flames - end of story. A
fusible resistor may or may not have a specific fusing current, in any case
it is far from a precise value.

One of your resistors has 83 % of the desired value, so it will likely
go open very close to the same conditions as one with the full value.



............. Phil