andrewty

nice instructable.Modern Lead Acid batteries do not suit >14V charging despite what some of the other comments say.The correct charging voltage for the modern chemistry in a Lead Acid battery is 13.8Vdc, unless the manufacturer tells you otherwise.The design uses a constant current pre-regulator.That acts as a short circuit protector. It does not need another protection device.Had this charger used a linear regulator, then it would become hot if short circuited and passing the set current into a near zero ohms load. But this charger is made up from pre-assembled switcher regulators. They do not overheat when taken to their maximum.I repeat, this battery charger is excellent and when used correctly will not damage modern Lead Acid batteries.Well done.

This instructable is much better than the usual rubbish we get here.Well done.I did not know the 10W rule !I'll have to keep that >=2A loading in mind.

Is there any chance you can edit out your spelling errors?

Be careful with UK knife law.One must have good reason to have a knife in a place to which the public have access.There are a few exceptions:eg, a folding type penknife with a blade less than 75mm long and the blade does not lock open.

You were doing just fine until you replied with this. Now I am gone. Don't ask for help with that attitude.

Ball and roller bearings are made in different "speed" grades.The lowest speed are the tightest, with a tiny diametrical clearance.The highest speed have the largest diametrical clearance.One can check the clearance by trying to rock the innner against the outer. A slow version will have very little sideways rocking. After cleaning this will be more easily detectable.Cheap bearings will probably have such wide tolerances that testing a group of cleaned versions will give a very wide range of apparent rocking/slackness. some due to balls of different diameters, some due to out of round of thei nner and/or outer and some due to different diametrical clearance.

UK builders:It is illegal to hunt wirh a bow anywhere in the UK.Not birds, not animals, not fish. Nothing can be hunted with an arrow.Crossbows are illegal for hunting.Target points are OK for target shooting.As far as I know all other points are illegal.

Where are the instructions for fusing?

"This is the step down transformer which converts 230v into 12v and 24v DC as per need."No !A transformer changes the voltage of AC.It converts 230Vac to 12Vac and 24Vac. It does not change to 12v and 24v DC as per need !!!!!!

Useless.Where is the schematic to show how to convert low voltage AC to DC?Where is the schematic to show how to adjust the rectified and smoothed DC to a lower voltage?

"Use the step down transformer to convert 230v AC into 9v DC."How? Where are the construction details?"Use 10k Trimpot for Variable supply!!"Where are the construction details?

very approximate.Your answer depneds on the difference between two very similar valuesThe inductive impedance is too low for this method to work.You need to use a much higher frequency and/or a much higher inductance.I suggest the voltage loss across the inductor be smilar to the voltage loss across the reference resistor.That would give you some chance of being nearly accurate to two significant figures.As is, your inductor measured value is not even accurate to 1 significant figure.

Very approximate.Your answer depends on the difference between two very similar valuesThe inductive impedance is too low for this method to work well.You need to use a much higher frequency and/or a much higher inductance.I suggest the voltage loss across the inductor be similar to the voltage loss across the reference resistor.That would give you some chance of being nearly accurate to two significant figures.As is, your inductor measured value is not even accurate to 1 significant figure.

his arithmetic is riddled with mistakes. Can't you see that?

I use a pair of croc clips on leads with a 2k2 resistor soldered in circuit.The 2k2 limits the current of a 63V fully charged capacitor to <=29mApkA 2W resistor will initially get very warm if trying to discharge a 15mF cap from 63Vdc but it does cool down quite quickly as the charge dissipates. The 2k2 on a 15mF will be down to <5% of starting voltage in ~160seconds.

Instructables is about learning how to do "stuff".it's the learning that is important.

I am completely out of theloop and very definitely grey haired.

I do the opposite when rolling twisting the bit.I offer up the cutting lip to the stone and try to get the correct angle. You said 60degrees, that's close enough, but 56° to 59° is probably better. This gets closer to the preferred 114° to 118° tip.Once I have the drill bit at the correct angle to the face of the stone. I rotate the bit until the cutting lip to be sharpened is horizontal. The drill is now at right angles to the stone face, the lip is horizontal and the bit axis is at ~ 60°.Now gently push in holding those three angles accurately, the horizontal and the 60° to start grinding the cutting lip. Now I start to tilt the bit down at the blunt end and at the same time rotate the bit clockwise so that the lip comes up and away from the stone. The area beh...

I do the opposite when rolling twisting the bit.I offer up the cutting lip to the stone and try to get the correct angle. You said 60degrees, that's close enough, but 56° to 59° is probably better. This gets closer to the preferred 114° to 118° tip.Once I have the drill bit at the correct angle to the face of the stone. I rotate the bit until the cutting lip to be sharpened is horizontal. The drill is now at right angles to the stone face, the lip is horizontal and the bit axis is at ~ 60°.Now gently push in holding those three angles accurately, the horizontal and the 60° to start grinding the cutting lip. Now I start to tilt the bit down at the blunt end and at the same time rotate the bit clockwise so that the lip comes up and away from the stone. The area behind the lip now gets ground into that strong curved shape, you were talking about. The clockwise rotation is probably about 60degrees (one sixth of a whole turn). One does not want to rotate so far that the opposite lip hits the stone grinder.Rotate the bit 180° and offer the other cutting lip to the stone face. Set your two angles horizontal and 60° and start grinding the lip and then the back behind the lip.Check looking at the end and see how equal the two cutting lips are. If one is slightly short, then that one needs a regrind.. Keep checking and regrinding till the two lips match.To strenthen the cutting lip for very hard materials, I sometimes add an extra grind to the front face of the lip. This flattens off the helix angle to a new flat face that aligns with the main axis of the bit. This leaves the lip with more metal around it. I use a 300 grit diamond file to form this front face.You can also use this to narrow the chisel point to about half it's former width.When sharpening lathe turning tools, one goes even further and puts a -ve rake onto that front edge for even more strength.

The blacksmith I worked with before I left school 49years ago told me that the anvil sits on a log that is 6feet below floor level. A log about about 7.5feet long gets the anvil to a nice working height.It's the springiness of the log down/along the grain that gives the anvil it's rebound ability.

The balcksmith I worked with before I left school 47years ago told me that the anvil sits on a log that is 6feet below floor level. A log about bout 7.5feet long gets the anvil to a nice working height.It's the springiness of the log down the grain that gives the anvil it's rebound ability.

The balcksmith I worked with before I left school 49years ago told me that the anvil sits on a log that is 6feet below floor level. A log about bout 7.5feet long gets the anvil to a nice working height.It's the springiness of the log down the grain that gives the anvil it's rebound ability.

You could do with changing the title to include "DC Watt meter"You would need a multiplying function to calculate instantaneous I * V to generate a watt value.You can't just measure Irms and Vrms and just multiply. That excludes the load phase.Take a capacitor across the AC voltage. It absorbs virtually zero power even though the current is measured as significant mAac, or Aac.Same for an inductor. The reactive element of the load does not absorb power. Only the resistive part of the load absorbs power.

you could do with changing the title to include "DC Watt meter"You would need a multiplying function to calcukate instantaneous I * V to generate a watt value.You can't just measure Irms and Vrms and just multiply. That excludes the load phase.Take a capacitor across the AC voltage. It absorbs virtually zero power even though the current is measured as significant mAac or Aac.

Have a look at the chip dissipation when delivering power to the 4ohms loads.The graph shows ~23W being dissipated when 1W is being delivered.the heatsink will need to be very large to get rid of 23W if you plan to have continuous average outputs of 1W into your loads.Look at the THD vs output graph.the signal distortion rises rapidly as the output passes above 15W It passes 0.1% THD when the output reaches ~18W into 4ohms when the supply has sagged to 14.4Vdc.The Absolute maximum operating voltage is specified as 18Vdc. Allowing for voltage sag at the supply pins makes this a quad 18W amplifier, not 40W.

A next to useless instructible."you'll need a 3D printer," What !

the isolated supply feeds the Device Under Test (DUT).The isolated supply is NOT used to supply the grounded oscilloscope.Never probe anything with the scope probe deliberately ungrounded. or use the specialised differential probe that costs more than most scopes.

Using two identical mains transformers back to back gives an output voltage that equals the input, when there is no load current.As soon a load current is demanded, the output voltage drops.The voltage drop under full power load is roughly two times the voltage regulation of the mains transformer.eg, using two 230:55Vac 8% regulation 500VA mains transformers will give a 1:1 input to output voltage on any EU harmonised supply when no load current is drawn.When the 500W resistive load is applied, the voltage will drop to ~inputVac/(1+0.08)² ~86% input Vac. This resulting isolated voltage is well below the minimum voltage specified for an EU harmonised voltage.

I have to ask the same question.We have our newly boxed isolation transformer. It has a 3pin plug top ready to plug into the mains wall socket. It has a 3pin output socket. It has an MCB on the input and another MCB on the output.How do we wire up the Protective earths (PE)?Do we wire the enclosure to the PE?Do we wire the output socket to the PE?Do we fit a GFI (RCD, RCBO) to the input wiring?Do we fit a GFI to the output wiring?

Are the gates to Q1 & Q3 (Pchannel mosFETS) drawn upside down?

I try to download the 11steps, but the screen just refreshes and shows step 1 with the comments following on.I tried using the "view all steps" icon but it does the same taking me straight back to showing step 1.What's wrong?

where are the instructions.Many pics but no details to manufacture the mechanisms.Not much about how to control the electronics.

WD40 is not a good lubricant for non rusty threads. WD40 is pretty poor as a penetrant.Use a penetrating lubricant formulated for that duty.many better suggestions in the earlier comments.

For, connecting the AC bulb to the relay properly:Connect live wire from AC wall outlet to Common port on relay and one terminal of AC bulb to Normally open terminal of Relay. Then, Connect the other terminal of AC bulb to GND on the AC wall outlet.NO !!!!connetc the other terminal of Mains bulb to NEUTRAL, not to GND.

For, connecting the AC bulb to the relay properly:Connect live wire from AC wall outlet to Common port on relay and one terminal of AC bulb to Normally open terminal of Relay. Then, Connect the other terminal of AC bulb to GND on the AC wall outlet.NO !!!!Connect the other terminal of Mains bulb to NEUTRAL, not to GND.

the critical part is crimping the RJ onto the cable ends.But the pic is so bad that I can't see any detail !1 out 10

How good are the drawer slides at holding an accurate Up/Down motion?

Tungsten filament lamps run very hot.Fluorescents run a lot cooler.LED lamps are cooler still.Most can be touched without burning ones fingers.The exposed heatsink is usually the hottest part you can touch and it needs to be cooled to ensure a long life for the LEDs. They do not tolerate heat.A bit of air circulation helps, as does a big surface area to transfer heat to the surrounding air.

Is the black a corrsion product of the silver?How do you convert that back to silver?Other wise the silver gets thinner, until there is no silver left !

How you do send a signal to pull the door handle?

Could you explain the operation?

What is the other component on the plug in board?I can see the IR receiver at the top and the three lead out wires at the bottom.

Could add some information on timing?How fast can they be switched with the controller?

Yes.You must take account of the voltage.Were the four batteries in series, or in parallel, or in a series parallel arrangement?Without this bit of information we cannot follow your analysis.

10400mAhr ?Why milli-amperes?It would be more comprehensible to state 10.4Ahr just like any other big battery.We are all used to evaluating the Ahr of car and leisure batteries. I recently bought a 22Ahr 3.7V lion battery pack.With that info I can see immediately that it is a big battery and what output voltage to expect. I can see that if I draw 1A it is likely to last ~22hours.

10400mAhr ?Why milli-amperes?It would be more comprehensible to state 10.4Ahr just like any other big battery.We are all used to evaluating the Ahr of car and leisure batteries. I recently bought a 22Ahr 3.7V lion battery pack.With that info I can see immediately that it is a big battery and what outpyt voltage to expect. I can see that if I draw 1A it is likely to last ~22hours.

if your motor is 5A thenthe mosFET must have a current rating exceeding 15A (3 times the normal maximum current)the irf530 has a max cold rating of only 14AThe 540 is much higher IdOr use a low Rds on type eg irlu8726 max I=80A and Rds on < 0.006ohms for best efficiency and cooler operation.

a ¼HP 12V motor will draw a lot of current. And even more when starting.Use a very high Id device with a very low Rds on.The example I gave above irlu8726 might do the job, or irfb3607 80A, 0.009ohmsAt 3 times the running current you will need a rating of >50A mosFET. 1HP=746W, ¼HP=186.5Wrunning current is ~186.5W/12V = 15.5A 3times that is ~47A ratingThe 555 timer will need a driver to charge up the gate capacitance. This becomes a much more onerous design.

the Ultra violet is dangerous to eyes.Will this exposed LED emit enough UV to damage our eyes?

remove your instructible and read all the others.Try reading the datasheet.

I agree, this instructable is full of mistakes.The writer just does not understand how to get a 5V output.The LED could have been used as a minimum current load for the lm7805 series regulator. Some datasheets state that the minimum current should be 5mA and a few state 10mA minimum.Using a series resistor to limit the LED current is mandatory.For 5V out and 1.8Vf for the LED you need a resistor value of (5V-1.8V)/0.01mA = 320ohms, use a 330r for near 10mA min draw, or use 680r for 5mA min draw.If one decides they need reverse polarity protection then one can use the forward diode on the output. But we need to compensate for the forward voltage drop by adding a similar diode into the GND (labeled 2) of the regulator.The Vf (Vdrops) of the two diodes won't be identical, but close enough ...

I agree, this instructable is full of mistakes.The writer just does not understand how to get a 5V output.The LED could have been used as a minimum current load for the lm7805 series regulator. Some datasheets state that the minimum current should be 5mA and a few state 10mA minimum.Using a series resistor to limit the LED current is mandatory.For 5V out and 1.8Vf for the LED you need a resistor value of (5V-1.8V)/0.01mA = 320ohms, use a 330r for near 10mA min draw, or use 680r for 5mA min draw.If one decides they need reverse polarity protection then one can use the forward diode on the output. But we need to compensate for the forward voltage drop by adding a similar diode into the GND (labeled 2) of the regulator.The Vf (Vdrops) of the two diodes won't be identical, but close enough to achieve the USB 5V supply voltage.

Agreed.This instructible is a complete waste of other Builders' time.It is a "how NOT to" ruin a useful idea.Read the lm7805 datasheet to see how to do it properly.

Please do a couple of instructables for telescope making.Can't get the reply to work so adding comment here instead.

acetylene is too hot for melting aluminium.Propane is plenty hot enough.Oxygen is also too hot.A good propane/air burner will melt lead and aluminium.But probably not cast iron. That needs quite a bit more heat. Oxy/propane is probably OK for cast iron.

We had quick releases on my school benches (4 off and over ten years as teacher). They never gave any trouble.I have one at home on my woodwork bench. It too has been totally reliable.Some manufacturer (not in the UK) must be making a codswallop of making bad clones.