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This is instructable assumes the reader to be compident in soldering. Use a very low resistance Mosfet ideally 0.2ohms or less and acurrent capability above 10 amps (the greater the current capacity the less need of a heat sink I used a 60amp continous current transister).

Changing the value of R3 will change the flash frequency. The Battery, Lamp Flasher circiut and switch are all in Series and therefore can be put in any order.

PARTS

Strip Baord
1 x Hex MOSFET transister N channel (min rating 3 times bulb current)
1 x PNP transister
22 awg wire (shorting links)
18 awg wire to connect to power lamps and switch
220K Resister
22K Resister
6K8 Resister
1n4001 Diode
100uF Capaciter min 25v
10uF Capaciter min 25v
TIC TAK mints packet
Insulation Tape

TOOLS

Solder
Sodering Iron
Craft Knife
Snips
Saw

Step 1: Biuld the Circiut


This circiut is very simple and can be made on a small piece of strip board.

Note The tall components (transister and Caps) lay flat, this is essential so as to fit in a TIC TAC box

1
Locate this point and cut the track.

2 Solder in shorting links

3 Solder in Diode and Resistors

Finaly solder in Transistors and Caps, (Note caps -ve)

Step 2: Fit in the Box


First Remove sticky lable over the lid

using a craft knife cut a small hole for the wire to exit the box

Place the board inside the box and close the lid around the wires

The final thing to do using insulation tape is to tape around the top of the lid and the box. this effectivly replaces the origanal lable and secures the lid to the box.
<p>Thanks lrdforster, it works perfect!</p><p>I had to add a Capacitor between Drain and Source of the mosfet, because my bike has ripple and it trigger the transistor randomly. </p><p>The Image is in the original flasher box of the bike.</p>
Hi Irdforster, <br>Great Circuit. It was Awesome. By the way, can I ask something? Where's the Flasher unit here? Cause I really need to know where's the LED or bulb that would flash here. THANKS!
The Circuit Diagram on the left hand side is the flasher unit and the circuit on the Right (consisting of the 12v Battery, left and right indicators and switch). <br> <br>Please Do Not confuse the bottom connection of the circuit to be Ground or 0v. <br> <br>Thi two circuits form a simple closed loop 12v from the battery through the flasher circuit, through the switch (still 12v side of the bulb/LED) then back to 0v. I hope this helps
That part list said NPN transistor while the schematic said PNP ...<br>which one is correct?
my mistake should read pnp thanks for pointing it out<br>
Can this circuit be used for LEDs instead of bulbs
Yes you can use LED Bulbs or single LED's but you will probably need load resistors equal to those used for conventional flasher units. If you want a cct of about 1/2 hz and single LED I would use 555 timer. try <a href="http://http://freespace.virgin.net/matt.waite/resource/handy/pinouts/555/" rel="nofollow">http://freespace.virgin.net/matt.waite/resource/handy/pinouts/555/ </a>as a site for the astable circuit, Id use, the cost difference is negligableHowever you may need a transister to drive the LED or LED's R1= 3k3 R2= 330k C1= 4u7f This is 50% duty cycle but you can try other prefered values and get your own match
<a href="http://freespace.virgin.net/matt.waite/resource/handy/pinouts/555/" rel="nofollow">freespace.virgin.net/matt.waite/resource/handy/pinouts/555/</a>

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