Here are some of 6V to 12V DC converter circuits that can be used to convert a small voltage of about 6 volts to a higher voltage of 12 volts but ofcourse with a lower current rating.
6 volts to 12 volts converters
This inverter circuit can provide up to 800mA of 12V power from a 6V supply. For example, you could run 12V car accessories in a 6V car. The circuit is simple, about 75% efficient and quite useful. By changing just a few components, you can also modify it for different voltages.
R1, R4 - 2.2K 1/4W Resistor
R2, R3 - 4.7K 1/4W Resistor
R5 - 1K 1/4W Resistor
R6 - 1.5K 1/4W Resistor
R7 - 33K 1/4W Resistor
R8 - 10K 1/4W Resistor
C1,C2 - 0.1uF Ceramic Disc Capacitor
C3 - 470uF 25V Electrolytic Capcitor
D1 - 1N914 Diode
D2 - 1N4004 Diode
D3 - 12V 400mW Zener Diode
Q1, Q2, Q4 - BC547 NPN Transistor
Q3 - BD679 NPN Transistor
L1 - See Notes on the website
MISC - Heatsink For Q3, Binding Posts (For Input/Output), Wire, Board
This 6V to 12V converter circuit is made with an IC from SGS with several additional components. The IC is a TDA2003 but it can be replaced with a TDA2002.
The cost of building the 6volts to 12 volts converter should be low enough to justify constructing it instead of modifying the entire equipment setup to work directly with a 6 volts power supply. The two principles of simplicity and functions properly without the need of the transformer.
This is a Simple Switcher step-up voltage regulator made by National Semiconductor, (part number LM2577-ADJ). Together with a few extra components, a heat sink and some wiring, it is possible to generate over 1A from the battery of an Austin. The output connector is taken from a car charger extension lead, so that a phone or a sat-nav just plugs straight in.
This 6V to 12V dc-dc boost converter can drive a load in 12V about 3A current.The 555 timer IC is operated in astable mode, generates about 29Khz frequency of about 54% duty cycle drives the input of TIP41C transistor.1000uF capacitor smoothens the output voltage of the dc-dc converter.LED and 1.5Kohm resistor serves as indicator and load for output stability when no load is connected.You can add a 12V zener diode (1N5242B)across output to ground for further output stability.
Do you know some other designs of 6v to 12v converters? Then please write a comment and post the links in it. We will read it and add it to this list.