Wirewound Cement Resistor Ceramic explanation

[bohaboha]

exemoel :10w 20Rj what Rj means? is there anyone who can refer where I can buy 3w + 30kohms cement resistors or higher value for example 40kohms but 3w or what I can I use instead if I can not find

[eccerr0r]

10W = 10 watts (ceramic block)
20 = ohms
R = Resistor, or the decimal point
j = 5% tolerance.

So no, the 30KΩ resistors won't be the same thing. You could get two 10Ω 5W resistors and stick in series.

Incidentally I don't see much use for a 10W 20KΩ+ resistor these days in modern consumer electronics... You'd need hundreds of volts to dissipate that much power to need a resistor that big and it's indeed just wasting that power. Vacuum tube circuits (including CRTs)!? All bets are off.

[bohaboha]

Thank you. but you did not answer my second question if you can suggest something,grateful for all the suggestions that can enrich my searches

[eccerr0r]

All power resistors will be ceramic. Pretty much everything else has a risk of melting or immolating. I already gave you one option if you can't find the exact value, but they too will be ceramic.
I don't know what sources you have available locally. I'm sure mouser or digikey will have exact replacement units.

[redwire]

Modern resistors and capacitors follow the EIA standard for values. Example is the EIA-12 is twelve values for the decade, used for parts that have +/-10% tolerance: 100, 120, 150, 180, 220, 270, 330, 390, 470, 560, 680, 820
In that your 30k woud be closest to 27k or 33k, and 40k closest to 39k.

Next is for +/-5% EIA-24 values for the decade: 100, 110, 120, 130, 150, 160, 180, 200, 220, 240, 270, 300, 330, 360, 390, 430, 470, 510, 560, 620, 680, 750, 820, 910.

But it would be still hard to find 40k at several watts, they are not popular and not a standard value really.

[bohaboha]

Thanks eccerr0r and redwire the two 10k ohms are not enough and as redwire said it is not easy to find the 40k then what can you have instead?

[momaka]

Perhaps get 3x 10-KOhms 1-Watt resistors and hook them up in series. Total resistance will be exactly 30 KOhms and the power ratings add up - i.e. 1W+1W+1W = 3W.

[bohaboha]

I thought so but where can you find 10k 1w the ones I find are 5w we are talking about Wirewound Cement Resistor of course but it gets clumsy there are no other alternatives?

[stj]

for 1w you can use metal oxide / metal film type

[bohaboha]

What I need should be 3w and +30k

[R_J]

Originally Posted by bohaboha

What I need should be 3w and +30k

Here:
https://www.mouser.com/c/passive-com...nce=30%20kOhms

[bohaboha]

thank you