Normally general bicycle will systematically give the light at night with a light bulb. By will receive the electric energy from the dynamo. But this system is defective straight that when stop spin a bicycle. As a result will make a light bulb switches off problem this solution so. There is the battery upwards. For the electric energy replaces the dynamo which certainly this system has to have fire package gives with the battery with. Come to see model the plan is or work system circuit Bicycle Power supply regulator. Follow the circuit see not difficult already by this system designs to come to for voltage source 6V. See the detail in the circuit or seek you want to read the detail more than this as a result can see from http://www.nscl.msu.edu/~daniel/regulator.html

For the work experiences general that want power supply LAB. I thinks L200 DC Variable power Circuit. May like you , because of give Volt range about 3V-15V and Current 2A normal. When , you see the circuit. May search eyes and the integrated circuit that use be number L200 although old already. But still be usable well the interesting. This important circuit that should use Transformer that be appropriate be 12V sizes and should use 2A more than because get current that straight follow want certainly give testimony grandmother horn forget to stick let off the heat gives with, IC L200 with appropriately. The detail is other see in the circuit and from original website http://www.mitedu.freeserve.co.uk/Circuits/Power/l200var.html

One your friend beg for model the circuit about variable supply range 0-25V. I tries to search see meet voltage regulators circuits. The this be the circuit that use the transistor 2N3055 numbers are important equipment. Which be the equipment that seek good easy. fine P1 control current output the topmost. And fine P2 control Voltage range 0-25V. The detail is other invite read in original website http://www.redcircuits.com//Page36.htm

Simple Step up DC TO DC Converter by LM555
If you will take an interest to try build DC TO DC Converter step up Volt model base. I thinks , when you have evered to play IC LM555 that highly popular come to already. As a result is try lead it comes to use in this work sees ? From its circuit has can to transform 12V from is 18V by give current get tall about 3A. By P1 and P2 fine decorate the frequency are appropriate for make the circuit transforms well for the clearness of this circuit. I advises read to wasp in original website http://www.xs4all.nl/~jwasys/old/diy4.html#stepup better sir.

Somsak is person see the website of me take an interest try build Variable Regulater Switching LAB Supply. By fine decorate voltage output get 0-50V and fine current get 5A. I then choose this circuit , which use IC TL494 be pillar equipment (Switchmode Pulse Width Modulation Control Circuit). And use pretty litter transistor number MJ15004 then give current get enough tall. But should choose pot size modifies about 5A go up with. When see the circuit has already may inappropriate with a novice. Because use many equipments then the gift uses the tie perhaps specially with , be lucky sir.

In case of you want DC Voltage adapter circuit 1.4V sizes and use current about 100mA. I begs for to advise this circuit. Be the one choice because it easily but good effective sir. Use base equipment only mourn not ? only By voltage fall straddle diode 2 the . Be valuable about 1.4V take Voltage here go to be usable which be valuable be stable moderately sir.
Link

A younger brother of me takes an interest to want to try build Mini DC Voltage Regulate 12V to 9V circuit. But he has a condition that want to use old equipment comes to use. I then advise this circuit , because use the transistor number BD242,BC549 and other equipment. Again not ? which think seek easy certainly. By this circuit gives the trend about 1A only. By fine decorate P1 for control volt output , part P2 use for control current output. The detail is other see in the circuit.
Source:

If you are looking for DC Voltage Reulator be simple. That can give Current tall about 3A and fine voltage get from 0-30V. As a result please consider this circuit before, it is easy. Because of have no the integrated circuit. Use the transistor is a principle especially the number MJ3001. Usability just fine VR1 for control Volt output and choose the value Current get with S1. The detail is other see in the circuit help understand go up sir.

Source: http://www.geocities.com/mistertippy/schematics/jacobs.html

This is circuit high voltage Power Supply DC Adjustable Voltage 0-300V 0.1A max. It is a simple circuit which can provide an Variable voltage source of 0 to 311V by R3-500K
The supply is short ciruit proof and the current is limited to about 100mA.

Source: http://www.geocities.com/tjacodesign/300vsup/300vsup.html