Regardless of where you live, this voltage is too high and you’ll need to plug in a 5 volt adapter to get the right power for your device. There are many different reasons why you may need a 12V to 5V converter. If you are looking to reduce the supply and create a USB port then the Uctronics converter module could be the perfect solution for you. Few points worth mentioning: first, the “Cigar”, with its fixed USB output connector is providing voltage that is too high by proper USB standards. It could be due to old age or just bad quality. The difference is about 10% and I would consider it not usable. Second, most modules are capable of input voltages up to about 25 volts, but few can do 40 volts and higher. Kudos for that. Switching circuit properties Module

This module has the same connections as “Fine” but it is a bit larger. It was sold as “3A DC-DC 9V/12V/24V to 5V USB Step Down Power Module 2A Precise Vehicle Charger”. Voltage and current A load resistor or output circuit is a must at output end while implementing or testing it in a circuit to prevent zener diode from getting burn. Customers are overwhelmingly happy with the converter although it should be pointed out it can get hot if used for an extended period. Circuit 2 is a series Zener diode (or you could use a number of ordinary diodes in series to make up the voltage drop - say 12 x silicon diodes)I calculated the efficiency of each module per each type of load as: eff = Pin/Pout = (Vin*Iin)/(Vout*Iout) Here is the 12v to 5v dc converter circuit for low current applications (< 70 mA), mainly for taking reference signal/ voltage and in a small current draining circuit like an LED indicator. Circuit 4 is a three terminal regulator (IN-COM-OUT). This could represent a dedicated IC (such as a 7805) or a discrete circuit built from op amps / transistors etc. The schematic circuit shown below is for medium current circuits, it is useful for (1-70mA) medium current draining circuit eg. light emitting diode indicators, driver circuits, low voltage transistor operations, and many more.

These 5 circuits all work (i.e. they all produce 5V across a load) and they all have their pros and cons. Some work better than others in terms of protection, regulation and efficiency. Like most engineering problems, it's a trade off between simplicity, cost, efficiency, reliability etc. If this isn’t an option then you should take a look at social media and online forums. There are plenty of people online willing to share their experiences. This can help you to make the right decision regarding the best 12V to 5V converter. It measures just 8.2cm by 5.1cm and has a light on top to tell you it is in use. It can handle –35V and still output a steady 5V supply. However, you should note it is not waterproof and the power supply is non-isolated. The module is pre-built. All you have to do is connect the positive and negative terminals to the connections on the module board. A simple screw mechanism secures them in place. You can then plug in a USB cable and any device you like to get a stable 5V output. In general, it should be noted that the cheaper the product the more likely it is to be of poor quality. You should consider your budget and stretch it as much as possible to get the best possible converter.This circuit is a voltage divider schematic. You can design it for the required ‘output voltage’ by using this formula: And the winner is: “Fine”! This module is clearly the best for low power scenarios. When reaching currents of 100mA the differences between the 3 leading modules are minimal. You can run two LEDs in series across the resistor R2 while taking input from 12V lead-acid battery or a 12v adapter as an input. Ps. Ripple measured with a Tektronix oscilloscope, maybe it is also possible to measure it with a multimeter set to AC Volts. Generally, LM317 is a variable power supply IC that can provide a variable but regulated output voltage from 1.25 Volts to 37 volts depending on “Vref” (reference voltage), the voltage on pin number 1 (Adj.) which is reference voltage taken from a potentiometer. Adj. is voltage for adjustment. Below is a voltage divider circuit build using LM317 gives a fixed voltage of 5V at pin number 2.

The properly connected heat-ink is a must otherwise it can destroy the IC317. The input voltage must be 1.5V or more than the required output voltage. There are a few ways to get 5V from a 12V supply. Each has its advantages and disadvantages, so I've drawn up 5 basic circuits to show their pros and cons. Listed chip efficiency is within 5-10% of the measured module efficiency. The delta could be due to inefficiencies in the module itself or due to differences in the overall conditions (temperature, etc). You’ll then notice four terminals in a row. The two on the left are input, the two on the right output with the negative terminals next to each other for safety. Simply hook your wires up to the supply and the device. This device doesn’t just handle 12 volts. In fact, it can accommodate anything between 8V and 40V, converting it effortlessly into a stable 5V 3amp supply.The power supply for the test was providing 12V, but due to the voltage drop in the ammeter, the input voltage of the modules is a bit lower. Results It works, BUT most of the power is dissipated by the Zener diode. Not very efficient! On the other hand it does give a degree of regulation if the load changes. However, if you short circuit the output, the magic blue smoke will break free from the Zener... Such a short circuit may also damage the 12V source once the Zener is destroyed. It is suggested to connect the input capacitor ‘Cin’ to work (as well as at output ‘recommended’). A heat sink as shown in the below figure must be there to dissipate heat (kind of extra i/p potential). Of course, you may struggle to prove this is the case, leaving you without a device or a power supply converter. That tiny footprint saved me. Like I mentioned earlier, there are 9 TO 220 transistors, three with their own heatsinks, six more bonded to a common sink, 9 screw terminals for wiring the MOSFETs to their coil leads all crammed on a tiny business card sized computer development proto board.