I have some inexpensive 220 mAH C-type Ni-Mh batteries, https://www.amazon.co.uk/gp/product/B07BJ85NNZ The equivalent 3300 mAh C-Types I bought...

I have some inexpensive 220 mAH C-type Ni-Mh batteries, https://www.amazon.co.uk/gp/product/B07BJ85NNZ The equivalent 3300 mAh C-Types I bought a couple of years ago specified charging with 330 mA for 16 hours, but these new ones have no charging data. I have three soldered together and obviously charge in series. I've been using a trickle charge of 25 mA in the circuit of my curtain contr...

Hi, To attach an LM317 (for example) in the TO-220 format to the corresponding heat sink (see link below), is it useful to apply any thermal...

Hi, To attach an LM317 (for example) in the TO-220 format to the corresponding heat sink (see link below), is it useful to apply any thermal paste in addition to the flexible mat that comes with the heat sink? Thanks. -- XML combines

I want to use a hobby BLDC motor to power a compact high speed spindle to be used for engraving and the like. Mainly because they are so...

I want to use a hobby BLDC motor to power a compact high speed spindle to be used for engraving and the like. Mainly because they are so compact for the power and speed. I cannot find, for a price I can justify, a 24,000 to 40,000 RPM spindle that will fit in the space I want to put it. Looking at some hobby BLDC motors and then buying some to experiment with leads me to think that on...

I wish to experiment with valves (or tubes, if you prefer) and I shall begin by building a power supply. What voltages (at what currents)...

I wish to experiment with valves (or tubes, if you prefer) and I shall begin by building a power supply. What voltages (at what currents) should it supply? Where may I find circuits? Naturally, the devices used should be easily obtainable.

Hi, I want to learn a more and experiment with optical fibre, especially for communication. Does somebody here have any experience with...

Hi, I want to learn a more and experiment with optical fibre, especially for communication. Does somebody here have any experience with this (at a hobbyist level)? There seams to exist a kit called FO-30K, that just uses LEDs, optotransistors and plastic fibre. So it looks like this is a technology for hobbyies to play with. Concering fibre, I found something called "POF" (pla...

Hi, Does torque vs speed curve tell anything about the acceleration and deceleration characteristics of a stepper motor? Farah

Hi, Does torque vs speed curve tell anything about the acceleration and deceleration characteristics of a stepper motor? Farah

I bought one of these 24v DC motor controllers: https://www.ebay.com/itm/311703088756 It came with zero documentation. I found the basic...

I bought one of these 24v DC motor controllers: https://www.ebay.com/itm/311703088756 It came with zero documentation. I found the basic connections on the web, but nothing else. My question here is: it takes 12-24v DC in and with just a variac and bridge rectifier, it works. But would it work better with a regulated supply? I'm guessing not because of its own big cap and PWM output....

I suspected a CDI coil wouldn't put out enough voltage for the "energy transfer" -- the worst misnomer ever -- system and suggested shorting out...

I suspected a CDI coil wouldn't put out enough voltage for the "energy transfer" -- the worst misnomer ever -- system and suggested shorting out the spark plug electrode on one of the 2 cylinders by pounding the gap shut or stuffing it with a bit of foil. The theory was instead of jumping two gaps it would only need to jump one. The lower effective resistance would give a better spark on t...

In a hardware store, I saw a rectangular bar, 10" long, with two through holes, labeled "MAGNETIZE" and "DEMAGNETIZE". Presumably it has a...

In a hardware store, I saw a rectangular bar, 10" long, with two through holes, labeled "MAGNETIZE" and "DEMAGNETIZE". Presumably it has a battery compartment, though I didn't check. What's inside? -- Rich

Daimler and others already pointed out that the battery upon which Tesla's e-Semi is based does not exist. Tesla isn't just hoping a better...

Daimler and others already pointed out that the battery upon which Tesla's e-Semi is based does not exist. Tesla isn't just hoping a better battery will appear, however. They have good information on it and it isn't all that insider: http://www.businessinsider.com/new-discovery-could-be-death-blow-to-traditional-lithium-ion-batt eries-2017-12 https://www.theguardian.com/environment/2017/dec