Questions tagged [resistors]
A resistor obeys Ohm's law (\$\small V=I\cdot R\$); the current through it is equal to the voltage across it divided by the resistance (equivalently \$I=\frac{V}{R}\$).
4,699 questions
1 vote
1 answer
142 views
Darlington / Sziklai pair shunting resistor value
I'm trying to select an optimal emitter-base shunting resistor for a Sziklai pair (as far as I understand, a Darlington would have similar math), so I can achieve the highest possible transconductance ...
4 votes
5 answers
686 views
Effective resistance of a finite grid of resistor
I have computed the equivalent resistance between two opposite vertices of a square grid of resistor using just the rule for series/parallel. I found many discussions on these, but cannot find a ...
-3 votes
2 answers
167 views
How to size/calculate a resistor network where I can change the gain by 1dB with each switched in resistor? [closed]
I want to create a resistor network, where the gain changes by 1 dB per switching in each resistor See picture. Switches are all the same size. How would I size these resistor values so that the gain ...
0 votes
1 answer
149 views
Can a stone resistor with low values withstand 240 A pulsed current (1 Hz, 200 μs, 24 V)?
Pretty much as in the caption. I'm building a high pulse current system for a PHD project, using the capacitor bank discharge method to get the current I want. The main problem right now is a resistor ...
3 votes
7 answers
2k views
Why does a voltage divider work even with extreme resistor values?
I’m having trouble understanding voltage dividers. According to the standard formula: $$ V_{out} = V_{in} \cdot \frac{R_2}{R_1 + R_2} $$ If the two resistors, \$R_{1} = R_{2}\$, are equal in value ...
- 2,557
3 votes
4 answers
229 views
Non-linearity in presumably "linear" resistors
Summary. While investigating loudspeakers non-linearity, I found non-linear effects in the 0.1 Ohm resistors I used as current sensors. It turns out that self-made copper wire and metal film resistors ...
- 39
1 vote
1 answer
91 views
Blowing open 0402/1005 resistor by soldering it?
I am working on a board with 0402 (imperial) = 1005 metric resistors which have several thousands Ohm value (10k for inst.) and low voltages (1.8 to 5 V) - so no risk of exceeding the 63 - or 30 mW ...
- 317
4 votes
2 answers
215 views
Is optocoupler bias resistor and shunt regulator reference resistor value sufficient?
I am building one power supply and this is the circuit diagram of the isolation part. my question is : Is the value of the resistor that connected to the anode to the optocoupler(R18) and bias ...
- 153
1 vote
4 answers
122 views
Do I need a resistor between a VDC source and LEDs if there is a button? Does the button provide an internal resistance?
I'm messing with KiCAD. With that, I need to understand how to make circuits. Do I need that resistor? if so, before or after the switch? Thanks!
- 21
5 votes
3 answers
638 views
Tips to Identify a burnt resistor on PCB [closed]
I believe the PCB board may have taken a reverse polarity power input. I can see what looks like a burnt out resistor. Any tips how to identify this component at R20? This is beside the power input ...
- 69
1 vote
0 answers
54 views
RC filter for a fast delayed ramp
Consider simple RC networks with 3 external terminals (GND, IN, and OUT) and, at most, 4 total components. To be clear, each component is either a resistor or a capacitor. For a 1V voltage step on IN, ...
- 916
1 vote
0 answers
100 views
Understanding the topology of an analog multiplier & divider
I came across this multiplier/divider op-amp circuit from https://usermanual.wiki/Document/snla140b.1643036625/view. How does it work? I am trying to modify it to a squarer without supplying 1V at E2. ...
- 81
0 votes
1 answer
47 views
Shunt Resistor PCB Design Comparison Questions
Pad A has a direct PCB copper connection from the pad to the adjacent 16v power plane and a thru-hole 5 mOhm 600 mW resistor. Pad B has your standard SMD shunt resistor, 5 mOhm, 1 W, 1206 size, ...
- 1
-1 votes
2 answers
215 views
Why resistor instead of a fuse?
This is input of a non-isolated buck offline switching power supply (MP175GS with absolute maximum input voltage of 700v). Input is 100-265Vac. TVS is SMBJ440CA (713v clamping 600W BiDir). Resistor's ...
- 513
-2 votes
1 answer
143 views
Why does the resistor in this circuit not burn instantly? [closed]
This circuit is from BPS Space's Landing Model Rockets youtube series. It is the pyro channel circuit. The power supply is 12V. The terminal block connects to an e-match with a resistance of probably ...
- 107