Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [component-values]

57 questions
42
votes
3 answers

Why is the number 63 popular in electronics?

Capacitors have a voltage of 63V (not 60 or 65). Fuses have a value of 63A (not 60 or 65). And there exist more odd values in electronics... Who knows the history of this convention?
Jan van der Zanden
  • 537
  • 1
  • 4
  • 4
34
votes
3 answers

Why does the E12 resistor sequence use 27 and 33 instead of 26 and 32?

On the assumption that the E12 values were chosen to be equally spaced logarithmically between 10 and 100 ohms we get the ideal values of: 10.00 12.12 14.68 17.78 21.54 26.10 31.62 38.31 46.42 56.23 68.13 82.54 100.00 Therefore: the nominal value…
Dabbo
  • 579
  • 1
  • 3
  • 10
23
votes
2 answers

Why are there 3.15A fuses?

Why are there 3.15A fuses? Did someone decide that \$\pi\$A was a good rating? Or is it \$\sqrt{10}\$A they're aiming for? Is it even possible to make fuses with better than +/-5% tolerance?
Jasen Слава Україні
  • 31,874
  • 1
  • 31
  • 65
12
votes
1 answer

Resistor 100k¾ indicated in datasheet

I was reading the datasheet of a digital multimeter (DMM) and I came across a resistance value terminated with 3/4, like so: You can find it at the bottom of page 1-3 of the this document. What does it mean?
W.Thomas
  • 169
  • 5
11
votes
3 answers

Choose the better values (in terms of range) for resistors in this non-inverting op-amp circuit

These days I'm looking at operational amplifiers; from what I've seen, implementing them in a circuit is quite simple, at least when they are connected as "non-inverting". Determining the gain/amplification is possible by doing a calculation of two…
Mister D
  • 205
  • 1
  • 5
  • 13
9
votes
3 answers

How do you read this resistor value?

Home hobbyist here. I'm trying to be a little more automated in my reading of resistors. I've gotten pretty good at reading the 4 bands with the beige background, I find the colors easy to read, and the tolerance band obvious (gold or silver). But…
LarryBud
  • 455
  • 2
  • 9
8
votes
3 answers

How do I change the output voltage of the LM7805?

I read in the LM7805 datasheet that I can change the output voltage to not only 5 V, but to another value by changing the circuit resistance. How do I do that? From what I understand, to change the output voltage I saw this picture: However, I…
TOM
  • 81
  • 1
  • 3
6
votes
1 answer

Help me identify a resistor

I don't see what it is. I think it is a 56 Ω resistor. Is that correct?
Aliaksandr Shpak
  • 167
  • 4
6
votes
1 answer

4/5 band resistor - extra black band

I have two resistors which need to be replaced. I tried to determine the value, but it can't make sense of these black bands: For reference the bands are: brown - silver - green - brown - black brown - silver - red - brown - black Since a silver…
tehwalris
  • 746
  • 2
  • 8
  • 16
4
votes
1 answer

Possible to identify burnt component and its value?

The device is a Banana Pi M3, I accidentally short it out when I was playing around with my multimeter on the GPIO pins.... A noticeable spark came from that component in the above picture circled in red. Hopefully, only that component got burnt…
Tom L
  • 43
  • 4
4
votes
2 answers

Components with multiple possible values - how to designate on schematic?

Quite often it happens to me that values of resistors or capacitors don't play such a significant role. This is mainly the case with decoupling capacitors and e.g. LED series resistors. Often in decoupling caps their ESR and other characteristics…
Dzarda
  • 3,020
  • 1
  • 16
  • 23
3
votes
4 answers

Voltage rating of a Zener diode

How do we find the voltage rating of a Zener diode found alone by chance, when the only way to identify it is to inspect, test, and so on?
Nonok cantik
  • 399
  • 1
  • 9
3
votes
3 answers

Does "1KV" on this disc capacitor mean 1 kiloVolt?

One of my power supplies died. Investigation turned out that this capacitor is broken. "102" means 1nF, but does "1 KV" mean 1 kiloVolt or is that some sort of tolerance code? I've tried several "capacitor code calculators" but none of them mentions…
bos
  • 950
  • 1
  • 11
  • 24
2
votes
1 answer

Please identify this burnt SMD component in this LED driver PCB

This is an LED driver labeled as ED-SC 50W1200 (on the plastic housing) and no data is written on the back side of the PCB. The other side of the PCB is immersed in a black resin that is now locked as a solid and bound to all the components on the…
Unicornist
  • 123
  • 3
2
votes
1 answer

Buck converter with UC3843

I am building a simple buck converter circuit with a current-mode control IC, the UC3843. In the application note of the UC3843, a sample circuit is given: I am completely clueless about how these values should be set up. Also, is this even the…
Raza Nayaz
  • 31
  • 4
1
2 3 4