10k resistors: Is it just me?

[Karen O]

It seems that, rightly or wrongly, my stock of 10k resistors was always depleted and this is because of a predisposition I have to the use of this particular value.

I suspect this started with studying circuits in hobby mags, but was reinforced by my later experience of studying other peoples' designs in the workplace. Do you need to pull a logic line up to +5V? Use a 10k resistor! Even the chap who managed stock control in my longest employment noticed that we ordered far more 10k resistors (some in resistor network form) than any other value.

It is almost as though you need a good reason NOT to use a 10k resistor. Perhaps that's just me...?

Personally, the problem was such that I broke a personal oath that I wouldn't make any scavenge visits to Maplin in its moribund weeks. I bought a bag of 1000 10k resistors. Can I ever be forgiven?

[mole42uk]

I wondered why the suppliers were always out of stock of 10k…

[Radio Wrangler]

With enough 10k resistors, you can make up any other value...

David

[MrBungle]

A while ago RS mispriced some TE LR1F resistors for £3 a box. So I grabbed 2000 each of Major values. And you know what? Big 4000 sized boxes turned up. And you know what else? I haven’t used a single 10k resistor since I got them

[HamishBoxer]

ouch!

[broadgage]

10K is a nice round figure and I suspect that there is a tendency to use 10K when in fact a slightly higher or lower value would have been as suited, or even preferable.

Some fire alarm systems use a 10K resistor at the distant end of each circuit so as to prove that the circuit is intact to the end and not severed part way along.
Intruder alarms also use them to pass a small current round an anti tamper loop and detect any cutting of the wires.

[Radio1950]

1K for me.

[kalee20]

I actually tend to avoid 10kΩ as an arbitrary value such as a pull-up, unless there is a good reason to (such as it is the value required by the output of a calculation, or it gives an easy V to I ratio). Where there is freedom to choose values, such as a potential divider chain where ratios are important but actual values are not critical within a wide range, I go for values which result in bright colour bands. 10kΩ has so much brown and black in it, especially now that 3 bands plus multiplier is the norm, and the manufacturing processes are good enough that 1% is commonplace!

[mole42uk]

Originally Posted by MrBungle

A while ago RS mispriced some TE LR1F resistors for £3 a box. So I grabbed 2000 each of Major values. And you know what? Big 4000 sized boxes turned up. And you know what else? I haven’t used a single 10k resistor since I got them

Sell some to Karen!

[Paul Stenning]

Back in the 74xx TTL logic days we used lots of 4.7k, which was brighter coloured than 10k!

[Steve G4WCS]

Years and years ago when I worked in electronics we had a lazy circuit designer who couldn't be bothered working out resistor values or breadboarding to determine the correct fixed values to put in a circuit. Fast forward 20 odd years to where he has been promoted out of harm's way he is still referred to as "Trimpot Trevor".

[MrBungle]

Originally Posted by Paul Stenning

Back in the 74xx TTL logic days we used lots of 4.7k, which was brighter coloured than 10k!

I am guilty of this. I prefer 47k resistors in designs because it's my favourite colour bands

[Philips210]

Hi

In the past when I was building and experimenting with audio circuits then 10k resistors were used quite often. In TTL circuits, 4k7 and 470R were common values.

Talking of resistor values, many TV manufacturers often used values in the E6 range. Philips however, seemed to use quite a lot of values in the E12 range such as 12k, 56k etc.

Regards,
Symon

[newlite4]

Our primary lab sessions use OP-AMPs, chiefly UA741 and TL071. We always default to using 10k for the feedback resistor and 1k for the input resistor. When we had a surplus of around 10,000 22k resistors I suggested that we use these for the feedback resistors, this gave some relief from the usual brown black orange (or is it now brown black black red brown, hmm hang on, is that one a 120 ohm.....)
Neil

[G8HQP Dave]

For many purposes you can use an 8k2 resistor instead of 10k. Nobody ever designs a circuit specifying 8k2 so there will always be lots at the bottom of the drawer.

[woodchips]

As an antidote, have you noticed that people like Tektronix use a 937 ohm resistor in series with a trim pot?

I have wondered why they use such strange values where one 20% different wouldn't make any difference. Unless of course they buy 10,000 of every E96 value and have to use them somewhere?

If I need a pullup (or down) that isn't a critical value (yet to meet one), the packet around 1k to 100k with the most in it and first found gets used. I have often been asked "why the 6k8 (select rarely value here) pull up?". Answer "it will work and I have lots".

[julie_m]

If you use a BC547 to invert a 5V HC TTL logic signal, and both the base and collector resistors are 10kΩ, it will actually work fine with the transistor reversed (the base of a BC547 is in the middle). The "collector"-base voltage is just within the base-emitter junction's PIV, and the gain in this connection is just enough for it to work.

I did not tell you this, of course .....

[mole42uk]

Originally Posted by julie_m

I did not tell you this, of course .....

Hmmmm… so who told you?

[G8HQP Dave]

By an amazing coincidence a few hours after my last post above I was sorting though a box of stuff and came across a partly-built audio polyphase network for SSB. I started this many years ago but then got distracted by other things. The resistor value used was 8k2!