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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?
3D Printing Class
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 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.
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