Παρασκευή, 20 Μαρτίου 2015

Very easy way to find polarity of wires.

Which wire is the V+ ,which one the V-?There is an easy way to find out.Set your multimeter for voltage.

Connect the red probe to one wire the black to the other.You will get a reading to your multimeter.If this reading has a minus infront of it then you got your wires the other way around-the red probe touches the V- and the black the V+.

Now reverse the probes-touch the other wire with the red probe and the black probe accordingly.You will get a positive reading (without the minus infront).This means the red probe touches the V+ and the black the V-.That's it.
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Πέμπτη, 19 Μαρτίου 2015

Opel Corsa C oil and oil filter change.

Here is how to change the oil in your Opel Corsa C.Mine was made in 2001.

You don't need to lift the car to do this.You can reach the plug underneath from the front of the car.

the oil plug

Tools you are going to need.

A T45 torx key.
If the plug is too tight any pipe can be used as an extention.

a T45 torx key
Pipe as an extention of the torx key.

The procedure is divided into three parts.

part 1

part 2

part 3

Additionaly you need to change the oil filter every time you change the oil.

the oil filter

The oil filter plug might be too tight.I've used pliers to unscrew it.

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Κυριακή, 1 Μαρτίου 2015

X125 oil change and oil filter cleaning

Not many people know this but the Honda XR125 does have an oil filter.It's not a regular type oil filter but it is a centrifugal one placed inside the right side engine case.Not easy to access.No wander why many people neglect it so often.They are not even aware of its existance!
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LM386 on steroids -buffed up amplifier!

This is the buffed up version of the LM386 amplifier circuit- the LM386 on steroids!

The R resistor sets the gain.It can be between 3,3R and 820R .But be careful. Too small a resistor can result in a lot of noise.I've used a 520 ohm resistor here.

Here is the schematic.Original schematic diagram was found here.

Here is the actual pcb.

Last but not least-the actual pcb layout.Print it as is.

.Pcb file for Pcbwizzard

If you don't know how to make the pcb  take a look at this.

read also
1/2 watt mini amplifier (LM386)
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Τρίτη, 24 Φεβρουαρίου 2015

Steering wheel replacement Honda XR 125

 Someone knocked over my motorcycle causing severe damage to the steering wheel.

 The steering wheel got all bent up on the right side.

So,I got a new one and replaced it.

Replacing the steering wheel  is not that hard.
You can see the whole procedure in the video below.
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Πέμπτη, 19 Φεβρουαρίου 2015

Αλλαγή σπασμένου τιμονιού στο Honda XR-125.(βίντεο)

Κάποιος οδηγάρας έκανε όπισθεν φαίνεται και μου 'ριξε το μηχανάκι .Το ξανασήκωσε,γιατί το βρήκα όρθιο, αλλά να σε τί κατάσταση ήταν το τιμόνι.Το στράβωσε εντελώς στη δεξιά πλευρά.

Ρώτησα για γνήσιο τιμόνι Honda ,45-50 ευρώ μου είπαν.Τελικά αποφάσισα να βάλω ένα άφτερ μάρκετ στα 25 ευρώ σε χρώμα κάρμπον με μπάρα στη μέση από νικέλιο.

Η διαδικασία αλλαγής του τιμονιού δεν είναι ιδιαίτερα δύσκολη.Δείτε την στο βίντεο που ακολουθεί.

διάβασε επίσης
τρέχει βενζίνη απ'την υπερχείλιση
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Τετάρτη, 4 Φεβρουαρίου 2015

Tin case pill box preamplifier! (40db)

This is schematic of the circuit based on this one .I've used a TL072 op amp instead.

Explanation of the circuit

The preamp has a gain of 100 (40db).Gain is set  by two resistors 100k/1k=100

voltage divider
This arrangement is for a single power supply.The two 47K  resistors and the .1uF capacitor is a voltage divider.

high-pass cut off
The 10uf and the 1k resistor at the input of the preamp (pin 2) set the high-pass cut-off frequency.In plain words -in this circuit-smaller capacitor less bass.Bigger capacitor more bass.

I've housed my preamp in this tin case box!This helps avoid  various noises.

I'm using 5volts to power the preamp here.More volts give out more power.

variable gain

You can use a variable resistor in place of R4 for variable gain.

This preamp is outputting to a TDA7360 amplifier bridge amplifier (22 watts)  an older project of mine.

Here is the preamp with switch,led light and knob added.
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