All Questions
8 questions
3
votes
1
answer
6k
views
What is the difference between 4-, 5- and 6-band resistors?
I have been buying PSU DIY kits from eBay and I am learning a lot the PSUs that I've soldered together use the LM317 and the resistors used in R1 and R2 can change the outgoing voltage. The LM317 PSU ...
- 31
1
vote
2
answers
136
views
DIY flashlight - USB plug [closed]
I want to do something like the first of the gadgets in this video:
https://www.youtube.com/watch?v=aEo_nJ3iUYI (0:07 - 1:00)
It's a flashlight connected to the micro USB port in my cell phone, but ...
- 11
1
vote
0
answers
169
views
How to prevent a nichrome wire from melting under variable energy?
I’m experimenting with a DIY “sand battery”.
The “battery” is a pot lined inside with an insulator and filled with sand. The sand is heated by a nichrome wire placed at the bottom. The wire is ...
- 111
0
votes
2
answers
173
views
Potting DIY precision resistors made from resistance wires
I'm making a decade box and I need 100 Ω resistors for the hundreds increments range. I'm quite picky; I want the resistors to have 0.05% tolerance. I've checked online and 100 Ω resistors with that ...
- 409
0
votes
2
answers
3k
views
Why are resistors necessary in a summing audio circuit?
I am researching DIY stereo audio mixers (2 input, 1 out) -- there's lots of info out there -- but all the passive solutions (e.g., DIY Multi-Input Audio) include resistors, and I don't understand why ...
- 103
0
votes
1
answer
2k
views
Band selection circuit for SI4825 A10
Following the official schematic and guideline (AN738: Si4825/36-A
Antenna, Schematic, Layout, and Design Guidelines), I am building a Si825 A10-based radio receiver.
I am getting weak audio output ...
- 101
0
votes
2
answers
239
views
Designing a Dew Heater
I am planning to make a dew heater for a camera lens to get rid of condensation, using resistors wired in parallel, then distributing them around the circumference of the lens. Diameter of lens: 65mm
...
- 131
0
votes
1
answer
158
views
Astable Multivibrator using BC549s not oscillating
I just recently started learning about electrical engineering stuff, and since my final goal of building a Z80 Computer seems a bit far away, for now, I decided I'd make a simple clock I could ...
