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his is the Simple 12V To 24V DC-DC Converter Circuit Diagram. This simple DC-DC converter can provide up to 24V from a 12V source. It can be used to run radios, small lights, relays, horns and other 24V accessories from a 12V vehicle with a maximum draw of about 800mA.   Simple 12V To 24V DC-DC Converter Circuit Diagram It can be used to charge one 12V battery from another, or step up the voltage just enough to provide necessary overhead for a 12V linear regulator. Using one op-amp as a squarewave oscillator to ring an inductor and another op-amp in a feedback loop, it won't drift around under varying loads, providing a stable 24V source for many applications. With a wide adjustment in output this circuit has many uses. 

Some of you might wonder why a charger is needed at all, to charge a 12 Volt battery from a 12 Volt source! Well, firstly the “12 Volt” source will typically vary anywhere from 11 Volt to 15 Volt, and then a battery needs a controlled charge current and voltage, which cannot result from connecting it directly to a voltage source. The charger described here is intended for charging small 12 Volt lead acid batteries, such as the gelled or AGM batteries of capacities between about 2 and 10 Ah, using a car’s electrical system as power source, regardless of whether the car engine is running or not. I built this charger many years ago, I think I was still in school back then. On request of a reader of my web site, I’m publishing it now, despite being a rather crude circuit. 12V Powered 12V Lead Acid Battery Charger with Indicator It works, it is uncritical to build, and uses only easy-to-find parts, so it has something in its favor. The downside is mainly the low efficiency: This charger was...

Some of you might wonder why a charger is needed at all, to charge a 12 Volt battery from a 12 Volt source! Well, firstly the "12 Volt" source will typically vary anywhere from 11 Volt to 15 Volt, and then a battery needs a controlled charge current and voltage, which cannot result from connecting it directly to a voltage source. The charger described here is intended for charging small 12 Volt lead acid batteries, such as the gelled or AGM batteries of capacities between about 2 and 10 Ah, using a car's electrical system as power source, regardless of whether the car engine is running or not. I built this charger many years ago, I think I was still in school back then. On request of a reader of my web site, I'm publishing it now, despite being a rather crude circuit. It works, it is uncritical to build, and uses only easy-to-find parts, so it has something in its favor. The downside is mainly the low efficiency: This charger wastes about as much power as it puts into...

A very simple portable 12v to 250V converter can be designed using this circuit diagram. This 12 to 250V converter is designed for portable use with a 12 V car battery.A built astabil multivibrator T1 and T2 generates a rectangular wave at a frequency of 50 Hz. As T1 and T2 drive alternative exit stage system also works in "push-pull". When T1 lead by passing a current T3: T5 and that it engages the latter transistor connects to a half battery of 12 V secondary winding of the transformer Tr When T2 network drive, T6 transistor coupled to the battery the other half of the network adapter.  If it is used for output stages 40 411 RCA transistors, the current through secondary winding can be up to 10 A, giving a power output of 180 watts. If you use 2N3055 transistors, power output will be about 90 watts. Since the output transistors are driven to saturation, they have very high mounted radiators.Although circuit is simple construction and has high efficiency disadvantage is re...

Build a 12V 7.2Ah SMF Battery Charger Circuit Diagram . The LM317 is an adjustable three-terminal positive-voltage regulator capable of supplying more than 1.5A over an output-voltage range of 1.25 V to 37 V. It is exceptionally easy to use and requires only two external resistors, R2’ and R2” (R2= R2’+ R2”) to set the output voltage. Furthermore, both line and load regulation is better than standard fixed regulators. In addition to having higher performance than fixed regulators, this device includes on-chip current limiting thermal overload protection, and safe-operating-area protection. All overload protection remains fully functional, even if the ADJUST terminal is disconnected. By connecting a fixed resistor, R1 the ADJUST and OUTPUT terminals, the LM317 can function as a precision current regulator. An optional output capacitor can be added to improve transient response. Schematic Diagram using LM317   The ADJUST terminal can be bypassed to achieve very high ripple-rejectio...

This handy circuit can be used as a speed controller for a 12V motor rated up to 5A (continuous) or as a dimmer for a 12V halogen or standard incandescent lamp rated up to 50W. It varies the power to the load (motor or lamp) using pulse width modulation (PWM) at a pulse frequency of around 220Hz.  SILICON CHIP has produced a number of DC speed controllers over the years, the most recent being our high-power 24V 40A design featured in the March & April 2008 issues. Another very popular design is our 12V/24V 20A design featured in the June 1997 issue and we have also featured a number of reversible 12V designs.   Project Image :  12V Speed Controller/Dimmer Project Image For many applications though, most of these designs are over-kill and a much simpler circuit will suffice. Which is why we are presenting this basic design which uses a 7555 timer IC, a Mosfet and not much else. Being a simple design, it does not monitor motor back-EMF to provide improved speed regula...

This is the 12v Light / Dark Switch Circuit Diagram. Often, for certain low voltage lighting systems; you would like to turn off the lights during the bright light of the day.  Most commercial day/night switches are designed for AC lighting.  This hobby circuit below was designed for a 12v DC system.  But, it could be modified for other voltage as well.  It uses an inexpensive photo-transistor as the light detector.  An n-channel FET is used to switch power to the lights.  A transistor circuit is included to provide some hysteresis.   This keeps the circuit from fluttering the light during the transition from day to night and night to day.  It is recommended that a plastic tube be placed over the transistor to prevent it from being illuminated by the lights it is controlling.  By selecting the appropriate power FET, the circuit could control over 100 watts worth of 12v lighting.   (July 22, 2008) 12v Light / Dark Switch Circuit...