AC-DC & DC-DC Circuits

Although the 78xx series of voltage regulators are available with different current outputs, you can boost the available current output with this circuit. A power transistor is used to supply extra current to the load the regulator, maintaining a constant....

Using this circuit you can convert the 12V dc in to the 220V Ac. In this circuit 4047 is use to generate the square wave of 50hz and amplify the current and then amplify the voltage by using the step transformer...

Ever needed a low power 120volt AC power source for your car, van or truck? Well this circuit should do the trick for you. It will supply 15 watts of AC power to a device. It should power lamps, shavers, small stereos and small appliances. If you draw to....

R2 sets the output voltage. The maximum current is determined by the value of R3: the over-current protection circuitry inside the LM723 senses the voltage across R3 and starts shutting the output stage off as soon as this voltage approaches 0.65 V. This way....

With reference to the schematic, lamp, LP2, is a power-on indicator. The other lamp (lower) lights when the unit reaches its preset current limit. R5, C2, and Q10 (TO-3 case) operate as a capacitor multiplier. The 36 volt zener across C2 limits the maximum....

The power supply is based on the LM317 and LM337 variable 3-terminal regulators ICs, and while it is no powerhouse, it is quite satisfactory for testing most power amps, as long as there is no speaker connected...

If you want to try a higher voltage with your pedals, try this simple and easy voltage doubler circuit which uses an ICL7660 CMOS Voltage Converter Chip I have found that JFETs such as the J201 sound much better at 18V than they do at 9V with more clean to....

Our programmable MP3 player has an interface to an LCD with a HD44780 controller. These are alphanumeric LCDs with one to 4 lines of text and 16 to 40 characters per line. However, these LCDs (and LCDs in general) exist in two varieties: those that require a....

This simple circuit is a good solution to the powering a dual supply op amp from a single battery problem. The circuit simply takes a positive voltage and inverts it. It uses only one 555 timer and a few other passive components, so it doesn`t add much in....

I have had a lot of queries about getting a low power negative supply in cars, to power Linkwitz transform circuits and the like. There is a switchmode converter, but I must admit that it is overkill for what most people need. Another project describes how....

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This is a variable voltage 1.5A supply I threw together for bench experimenting for under $10. With a 24VDC wall wart, this board can produce anywhere from 23V to 1.2V..

Using the versatile L200 voltage regulator, this power supply has independent voltage and current limits. The mains transformer has a 12volt, 2 amp rated secondary, the primary winding should equal the electricity supply in your country, which is 240V here....

You need a power supply for a project, but only have a DC adapter available, so you can`t use my AC power adapter trick (Project 05). This little project came about because a reader had just this problem, and didn`t know what he could do..

Such supplies are often realised with dedicated integrated circuits nowadays but it`s still interesting to give a look at old designs to understand the basics...

Preamps may in some cases use a simple regulator, with the supplies taken from the main amp power supply. This can be a problem if the main amp is of very high power, as the supply voltage will be too high for 3-terminal regulator ICs. This will also be a....

This document describes how to construct a dual polarity linear power supply which can be configured for any positive or negative voltage between 1.2-35V. A power supply is the fundamental building block of all but the simplest of electronic devices. It....

The major disadvantages of usual linear power supplies are high power dissipation, the size and the appropriated weight. When looking for an alternative solution, I decided to use a switch mode power supply (SMPS). The efficiency of such power supplies is....

Since I have provided the schematic for John L Linsley-Hood`s Class-A amplifier, I felt that some readers may wish to experiment with the concept. Unfortunately, a very low ripple power supply is needed for all Class-A amps, and the most common solution is....

Sometimes amateurs like to home-brew their power supplies instead of purchasing one off the shelf at any of the major ham radio retail dealers. The advantage to rolling your own power supply is that it teaches us how they work and makes it easier to....

The Greinacher doubler circuit (a) transforms a grounded AC voltage (peak voltage Up) into symmetrical DC voltages of 1x Up each, thus producing 2x Up between outputs. If the input voltage is already symmetrical (e.g. as in an Obit), the Greinacher circuit....

The circuit is designed to provide protection to a DIY switching power supply for car amplifiers by shutting down under any or all of the three modes of protection (over voltage, under voltage and over temperature) with minimal components...

There will be many times where it is desirable to use the P05 supply module from a higher voltage source. For example, if you want to add balanced inputs to a power amplifier, then you need a +/-15V supply, but the amp`s supply voltage will be much too high....

This contributed project is a result of considerable collaboration between Sergio and myself, and should not be seen as necessarily a complete project in itself, but a stepping stone to understanding switching power supplies, how they work, and what you can....

Switch on one unit, and everything else you need turns on automatically. This can save the tedium of turning on half a dozen different things, when one should be enough! This is another project created purely from necessity. In my case, it was to switch....

As is commonly the case, this supply was born of necessity. There is absolutely nothing special about the circuit, except that as shown, it is quite capable of up to 20 Amps intermittently or 10A continuous. Simply use a bigger transformer, bridge rectifier....

How many times have you wished that there was a simple way to turn on that sub-woofer or some other piece of audio equipment, simply by sending it a signal? This ability is fairly common in commercial subs and some other gear, but there seems to be a....

The original version of P05 has been around for a very long time now (around 4 years), and there are some worthwhile reasons for the updates. Although the performance of the original was not lacking in any way, I decided to change to adjustable regulators.....

For the 60W amplifier, a nominal (full load) supply of +/- 35V is required, so a 25-0-25 secondary is ideal - however, see Updates, below. The circuit for the supply is shown below, and uses separate rectifiers, capacitors and fuses for each channel. Only....

The circuit is based on application of National Semiconductor. First is constituted by three voltage regulators LM338 [IC1-2-3] connected ``in parallel` `. The each one regulator has the possibility of giving 5 A in his output. Also exists the possibility to....

The basic requirements than one laboratory power supply, it is to provide voltages and currents of operation that need the usual units, to have low output resistance, low noise, small ripple and good stabilization. The above requirements are covered, from....

Proposed power supply for amplifier 100W v-mosfet [ 1 ] is what appears in the above form. It has separated supply for the various stages of supply, stage for power, stage for control, supply for preamplifier and for stage of protection. Whoever wants it can....