Power Supply Adapter

6V to 12V DC Voltage Doubler

2017-03-04T01:03:00.000-08:00

Here is the 6V to 12V DC voltage doubler circuit design, it also called DC voltage miltiplier or DC to DC converter. This dc voltage doubler circuit will need about 2A from the 6V input supply to produce the full 800mA at 12V for the power output.

This circuit is very useful to generate higher voltage from a low power source, but this circuit will deliver low output current. So it should only be used for low current driven applications. Also, the output voltage may be unstable, so a voltage regulator (IC78XX) of proper rating can be used regulation and smooth output. But voltage regulator IC itself consume some current, and reduce the deliverable current.

6V to 12V DC Voltage Doubler Parts List

R1, R4 = 2.2K
R2, R3 = 4.7K
R5 = 1K
R6 = 1.5K
R7 = 33K
R8 = 10K
C1,C2 = 0.1uF C3 = 470uF/25V
D1 = 1N914
D2 = 1N4004
D3 = 12V 400mW Zener Diode
Q1, Q2, Q4 = BC547
Q3 = BD679
L1 is a custom inductor wound with about 80 turns of 0.5mm magnet wire around a toroidal core with a 40mm outside diameter.

6V to 12V DC Voltage Doubler Circuit

Different values of D3 can be used to get different output voltages from about 0.6V to around 30V. Note that at higher voltages the circuit might not perform as well and may not produce as much current. You may also need to use a larger C3 for higher voltages and/or higher currents.
You are allowed use a larger value for capacitor C3 to provide better filtering.

Sealed Lead Acid (SLA) 12V Battery Charger with Current Limiting

2015-03-27T23:08:00.003-07:00

This is the circuit design of Smart Sealed Lead Acid (SLA) 12V Battery Charger featuretwith Current Limiting. The charger uses a two step process for charging SLA batteries – a current limited ‘fast’ mode followed by a constant voltage ‘float’ mode. Maximum charging current is 1A.

An onboard LED indicates when the charger is in ‘fast’ mode. When the LED goes out the battery is charged and the charger has switched to ‘float’ mode.

The best way to charge a Sealed Lead Acid (SLA) battery is with a current limited voltage regulator, allowing fast charging while limiting heat buildup and gassing. SLA batteries are made up of 2V (nominal) cells.

Therefore a 12V battery has 6 cells. The following parameters were used for this charger:

The charging current should be approximately 0.1 times the battery capacity. So, a 10Ah battery should be charged with a 1A current (10 x 0.1 = 1). This helps to ensure battery life.
The charging voltage is 2.45V per cell = 14.7V
Float charging voltage is 2.275V per cell = 13.65V

How Sealed Lead Acid (SLA) 12V Battery Charger Works

This two step battery charger works as follows:

Step 1. Charging starts at the maximum current limit. The battery terminal voltage will gradually increase until it reaches the regulator set voltage.
Step 2. As the battery becomes fully charged the current will start to decrease. When the charging current drops to around 140mA (see later) the regulator voltage is decreased to a safe float voltage at which the battery can be left on indefinitely.

Complete PDF document Smart Sealed Lead Acid (SLA) 12V Battery Charger can be downloaded from the following link:
Download File

Very Simple 35000 VDC High Voltage Power Supply (HV Generator)

2014-06-17T19:59:00.000-07:00

This is a basic knowledge about how to generate very high DC Voltage from 240V main AC home supply. The design of this circuit is very simple.

How the circuit works:

A light dimmer, a 1 pF capacitor and a 12 V car ignition coil form the simple line powered High Voltage (HV) generator. The current in the dimmer is shown in Fig. B. At times t1, t2,..., set by the dimmer switch, the inner triac of the dimmer switches on, and a very high and very fast current pulse charges the capacitor through the primary of the induction coil. Then at a rate of 120 times per second for a 60 Hz line, a very high voltage pulse appears at the secondary of the coil. To obtain an HV dc output, use a voltage doubler. D1 and D2 are selenium rectifiers (TV 18 Siemens or ITT) utilized for the supply of television sets. High value output shock protection resistors, R, are recommended when suitable.

Rectifier Circuit Without Diodes

2014-06-17T19:19:00.001-07:00

This the rectifier circuit to convert AC supply become DC supply which not required diode, in other words, this is an diodeless rectifier, rectifier circuit without diodes.

It`s common knowledge that when working with single-supply op amps, implementing simple functions in a bipolar signal environment can be difficult. Sometimes additional op amps and other electronic components are required. Taking that into consideration, can any advantage be attained from this mode The answer lies in this simple circuit. Requiring no diodes, the circuit is a high-precision full-wave rectifier with a liigli-frequency limitation equalling that of the op amps themselves.

The first amplifier rectifies negative input levels with an inverting gain of 2 and turns positive levels to zero.

The second amp, a noninverting summing amplifier, adds the inverted negative signal from the first amplifier to the original input signal. The net result is the traditional waveform produced by full-wave rectification. In spite of the limitation on the input signal amplitude (it must be less than VCCJZ), this circuit can be useful in a variety of setups.

Simple Split Power Supply 9V

2012-06-10T15:52:00.002-07:00

This is a simple circuit design of 9V split power supply. This power supply circuit delivers plus and minus 9V to substitute the two 9V batteries. The rectifier circuit is certainly two separate full-wave rectifiers fed from the secondary of the transformer. One full-wave rectifier consists of diodes Dl and D2, which produce +9 V, and then the other consists of D3 and 4, which produce -9 V.

Every single diode from every pair rectifies 6.3 VAC, half the secondary voltage, and charges the concerned filter capacitor to the peak value of the AC waveform, 6.3 x 1.414 = 8.9 V. Every single diode ought to have a Peak Inverse Voltage (PIV), rating which is at least twice the peak voltage from the transformer, 2x8.9=18 V. The 1N4001 features a PIV of 50V.

The transformer type is step down transformer with input / primary of 120V. You should be replace the transformer if your home electrical installation is use 220V.

+15V / 1A Regulated Power Supply using uA723

2012-04-22T00:10:00.000-07:00

This is the design diagram of +15V / 1A regulated power supply using uA723.
Circuit operation: The supply receives +20VDC from the rectifier / filter section (diode bridge). This is applied to pins 11 and 12 of the IC uA723, as well as to the collector of the 2N3055 series-pass transistor. The output voltage is simpled through R1 and R1, providing about 7V with respect to ground at pin 4. The reference terminal at pin 6 is tied directly to pin 5, the noninverting input of the error amplifier. For fine tuning output voltage, a potensiometer can be installed between R1 and R2. A 100 pF capacitor to pin 4 furnishes gain compesation for the amplifier.

Base drive to the 2N3055 pass transistor is furnished by pin 10 of the uA723. Since the desired output of the power supply is 1A, the maximal current limit is set to 1.5A by the resistor Rsc whose value is 0.433 Ohm.

A 100uF electrolytic condensator is used for ripple voltage reduction at the output. A 1K Ohm output resistor give stability for the power supply while in "no load" condition. The 2N3055 pass transistor have to be mounted on an adequate headsink for it stability and prevent overheating.

-15V / 1A Regulated DC Power Supply

2012-04-04T20:10:00.003-07:00

This is the scheme design of -15V / 1A Regulated DC Power Supply. It used uA723 precision voltage regulator and TIP105 PNP Epitaxial Silicon Darlington transistor. The supply receives -20V from the rectifier/filted which is fed to the collector of the Darlington PNP pass transistor, a TIP105. The base drive to the TIP105 is supplied through resistor R5. The base of the TIP105 is driven from Vz terminal at pin 9, which is the anode of a 6.2V zener diode that connects to the emitter of the uA723 output control transistor.

The method of providing the positive feedback required for foldback action is shown. This technique introduced positive feedback by increased current flow through resistor R1 and R2 under short-circuit conditions. This forward biased the emitter junction of the 2N2907 sensing transistor, which reduces base driver to the TIP105.

LM317T Voltage Regulator Circuit with Pass Transistor

2012-03-14T15:58:00.001-07:00

This is the schematic diagram of voltage regulator circuit with pass transostor. The regulator is based regulator IC of LM317T. The LM317T output current can be raised by utilizing an additional power transistor (on circuit, it is 2N2955) to share a portion of the total current. The amount of current sharing is established with a resistor placed in series with the LM317 input and a resistor placed in series with the emitter of the pass transistor.

In the above scheme design, the pass transistor will start conducting when the LM317 current reaches about 1 ampere, due to the voltage drop across the 0.7 ohm resistor. Current limiting happens at about 2 amperes for the LM317 which will drop about 1.4 volts across the 0.7 ohm resistor and make a 700 millivolt drop across the 0.3 ohm emitter resistor. Thus the total current is limited to about 2+ (.7/.3) = 4.3 amperes.

The input voltage will need to be about 5.5 volts higher than the output at full load and heat dissipation at full load would be about 23 watts, so a fairly large heatsink may be required for both the pass transistor and IC regulator LM317. The filter capacitor size can be approximated from C=IT/E where I is the current, T is the half cycle time (8.33 mS at 60 Hertz), and E is the fall in voltage that will happen during one half cycle. To keep the ripple voltage below 1 volt at 4.3 amperes, a 36,000 uF or greater filter capacitor is required. The power transformer should be large enough so that the peak input voltage to the regulator remains 5.5 volts above the output at full load, or 17.5 volts for a 12 volt output. This permits for a 3 volt drop throughout the regulator, as well as a 1.5 volt drop throughout the series resistor (0.7 ohm), and 1 volt of ripple generated by the filter capacitor. A bigger filter capacitor will minimize the input needs, although not significantly.

High Current 5V DC Power Supply

2012-02-27T20:05:00.000-08:00

This is the high current dc power supply circuit with 5V output. The high current regulator utilizes an extra winding or a separate transformer to deliver power for the LM317 regulator so that the pass transistors can run closer to saturation and increase performance. For excellent performance the voltage at the collectors of the two parallel 2N3055 pass transistors ought to be near to the output voltage. The LM317 needs a couple extra volts on the input side, plus the emitter/base drop of the 3055s, plus whatever is lost across the (0.1 ohm) equalizing resistors (1volt at 10A), so a separate transformer and rectifier/filter circuit is utilized which is several volts higher than the output voltage.

The LM317 will deliver more than 1A of electric current to drive the bases of the pass transistors and assumming a gain of 10 the combination ought to supply 15A or even more. The LM317 normally operates with a voltage variation of 1.2 between the output terminal and adjustment terminal and needs a minimal load of 10mA, so a 75 ohm resistor was selected that will draw (1.2/75 = 16mA). This same current flows via the emitter resistor of the 2N3904 which generates about a 1 volt drop across the 62 ohm resistor and 1.7 volts at the base. The output voltage is set using the voltage divider (1K/560) so that 1.7 volts is used to the 3904 base when the output is 5 volts. For 13 volt operation, the 1K resistor could be altered to about 3.6K. The regulator has no output short circuit protection so the output most likely ought to be fused.

9V Dual Polarity Power Supply from 9V Battery

2012-02-23T14:48:00.000-08:00

Here the schematic design of 9V dual polarity power supply from 9V battery. Dual-voltage power supply is necessary particularly for running the op-amps and some of the instrumentation amplifiers. Some low-power audio pre-amplifiers also use dual-voltage power source.

This circuit delivers both +9V as well as -9V DC output from a single 9V battery. It contains timer IC NE555 (IC1), negative-voltage regulator IC 7909 (IC2) along with several discrete parts.

Timer IC NE555 is set up as being a free-running oscillator. It generates approximately 100kHz frequency. An audio system would not pick up this frequency since it is above the audible assortment. Therefore a Villard cascade voltage multiplier is applied as the voltage booster. The boosted voltage is produced ripple-free and regulated to -9V by negative-voltage regulator LM7909.

The frequency of the squarewave generator is determined by the values of C1, R1 and R2. The frequency of the signal may slightly change with the temperature variation but the modification in frequency will not have an impact on the output voltage of the circuit.

Capacitors C3, C4, C5 and C6 and diodes D1, D2, D3 and D4 form the Villard cascade voltage multiplier. The output voltage from the Villard cascade voltage multiplier is fed to linear negative-voltage regulator IC2 to remove ripples and get precise -9V DC. Capacitors C7 and C8 present extra noise-filtering. The output from voltage regulator IC2 is -9V.

Build the circuit on a general-purpose PCB and enclose inside a appropriate case. Fix the 9V battery inside the case. At the front panel, connect three terminals for outputs. Take a note that this power supply tend to be utilized only for low-power applications/devices.

9V Dual Polarity Power Supply from 9V Battery, Circuit Source: Electronics For You Mag

Unregulated Split Power Supply for Audio Amplifier

2012-02-18T14:40:00.000-08:00

This is the unregulated Split power supply circuit, intended to supply the hi-fi audio amplifier. This power supply circuit is very simple, and no great skill is needed to assemble this circuit.

There are a few things one should be careful with, such as the routing of high current leads, but these are easily accomplished. The design diagram of this power supply is very simple. A 4 ampere fuse is used to secure the transformer and two LEDs at the end of this circuit are used to indicate power state On and Off. At the output there are 6 capacitors used, you can reduce the quantity of these filter capacitors to 2 or according to your own choice, but do not reduce the value of the capacitors too much because the lower value of capacitor can increase the "hum" sound of the amplifier.

Simple Variable Power Supply 0-15VDC / 1A

2012-02-11T00:14:00.000-08:00

This is the very simple general purpose variable power supply capable of delivering 0-15V DC output with about 1A electric current. The power supply circuit has regulated output and can be used for most small electronic circuit application.

This power supply circuit is very simple in construction, finding materials, easy and low cost. The output voltage is stabilized and regulated in the range of 0V to +15 V, supplied with a maximum current of 1 A. The adjustment is done in potensiometer R2. The Q1 is a classic power transistor and needs to be mounted on heatsink, and a constantly heated when working in the area of the peak current. The type of transformer is standard and can be found easily the market. The 4 rectifier diodes 1N4007 can be replaced with a standard 1A bridge diode.

Parts List:

R1 = 56ohm 2W
R2 = 330ohm Linear Potensiometer
C1 = 2200uF/35V
C2 = 100uF/35V
C3 = 10uF/25V
C4 = 220uF/25V
C5 = 100nF
GR1 = 4 x 1N4007
Q1 = 2N3055
T1 = 220V@18V 1.5A
D1 = 18V 1.5W zener

Simple variable power supply 0-15VDC / 1A, schematic diagram source: otenet.gr

12V Transformerless Power Supply

2012-02-03T16:49:00.000-08:00

Here the low power 12V transformerless power supply circuit with full-wave rectification. A lot of circuits could be powered straightaway in the electric mains using the support of a series capacitor (C1). The problem with this method is the fact that typically only one half cycle of the mains wave-form can be used to deliver a DC voltage. An obvious option is to work with a bridge rectifier to accomplish full-wave rectification, which improves the amount of current that can be delivered and makes it possible for the filter capacitor to become smaller sized. The associated circuit in fact does this, but in a clever manner that makes use of fewer parts. Right here we take benefit of the reality that a Zener diode can also be a standard diode that conducts electric current in the forward direction. During one half wave, the current flows via D1 through the load and back via D4, whilst during the other half wave it flows via D3 and D2. Keep in mind that with this circuit (and with the bridge rectifier version), the zero voltage reference of the DC voltage is not directly connected towards the neutral line of the 230V circuit.

This means that it is mostly not possible to work with this kind of supply to drive a TRIAC, that normally requires such a connection. Even so, circuits that utilize relays can benefit from full-wave rectification. The value of the supply voltage depends on the specifications of the Zener diodes which are applied, which can be freely selected. C2 have to be able to deal with at least this voltage. The level of current which can be supplied will depend on the capacitance of C1. With the given value of 220nF, the current is about 15mA. A final warning: this kind of circuit is directly connected to mains voltage, which can be lethal. You must certainly not come in get in touch with with this circuit directly without safety equipment! It is critical to mount this circuit safely and securely inside a appropriate case.

Lithium-ion (Li-ion) Battery Charger with MAX1879

2012-01-23T17:29:00.000-08:00

Above diagram is the circuit of Lithium-ion (Li-ion) battery charger which built based single chip MAX1879. This is the simple and low cost battery charger for single-cell Li+ battery that does not dissipate power (no heat.

The MAX1879, in conjunction with the AC linear transformer adapter and a PMOS FET, allows safe and fast charging of a single Li+ cell. The MAX1879 is not only an inductorless required solution, but also the lowest power dissipated solution among single-cell Li+ battery chargers.

The MAX1879 with a current limited linear wall adapter can produce the most economic and efficient solution for the single-cell Li+ off-line cradle charger, with virtually no power loss on the PMOS FET. It can be easily designed for handheld devices or battery packs without excessive power dissipation and heat problems.

Read detailed explanation about this Lithium-ion (Li-ion) battery charger circuit at maxim-ic.com

About MAX1879:
The MAX1879 single-cell lithium-ion (Li+) battery charger utilizes an efficient pulse-charging architecture to minimize power dissipation in portable devices. This architecture combines the efficiency of switch-mode chargers with the low cost and simplicity of linear chargers. This simple device, in conjunction with a current-limited wall cube and a PMOS transistor, allows safe and fast charging of a single Li+ cell.

MAX1879 Features:

Low Electronic Component Count, No Inductor
Simple Design Minimizes Heat
0.75% Accurate Battery Regulation
1.5µA (max) Battery Current Drain with Wall Cube Removed
Restart Charging at 4.0V
Battery-Full Indicator
Safely Precharges Near-Dead Cells
Automatic Power-Down when Power Source is Removed
Continuous Overvoltage and Overtemperature Protection
Charges 1 Cell from as Low as 4.5V
Pin-Compatible Upgrade to MAX1679

Download MAX1879 datasheet

Solid State Tesla Coil with 555 Timer

2012-01-16T17:16:00.000-08:00

Here the circuit diagram of solid state tesla coil with 555 timer.

Single transistor flyback driver induced a lot of complications on account of it really is operating principle. I received e-mails from those who had been unable to obtain it functional even after they are positive that their flyback and transistor is Okay. Moreover, because it is resonance frequency is determined by each individual a part of the method, any time you seek to draw an arc in the transformer, it alterations substantially in a lot of the circumstances. Simply because the operating frequency is vital for your security criteria, (each for mine and electrical power transistor's), I determined to generate it run on a continuous frequency and developed up yet another easy circuit, attempting to keep within the specified limits in the 555 timer.

Setting the operating frequency with an integrated timer is simple and practical. This schematic is absolutely nothing over the normal astable mode circuit layout having a traditional 555. It calls for only two resistors as well as a capacitor to set frequency (with duty cycle certainly) and a further resistor to ascertain electrical power transistor's base current, which it is possible to uncover it is optimal worth experimentally. I employed 1K for R1, two.2K for R2, and 10nF for C which produced circuit to run practically at 27 kHz theoretically, at %60 higher to %40 minimal duty cycle. You may easily calculate operating parameters in the resistance and capacitor values which has a tiny system that I've written.

Values offered for R1, R2 and C within this circuit diagram would be the ones employed on my prototype. You could possibly transform R1 and use a trimmer as a substitute for R2 to discover an optimum frequency / duty cycle blend to your flyback. By shifting C, you may possess the capacity to use increased or reduced resistor values, but tend not to desire as well minimal resistances (primarily for R1) for to not overload 555.

Energy transistor just isn't significant and any other could be applied so long as it really is qualities are equivalent or greater. Listed below are the technical datas for BD243C for comparison:

Bipolar NPN transistor : BD243C
Casing : TO220
Max. collector current : 6 Amperes
Max. complete energy : 65 Watts, even though situation is at 25 degrees Celsius
Transition frequency : 3 MHz
hFE (current obtain) : 30 at 300mA (minimal value)

PCB layout:

Detailed explanation about this circuit, visit this page: Solid State Tesla Coil with 555 Timer

Simple Power Supply Circuit for Laser

2012-01-09T19:15:00.000-08:00

This is a very simple high voltage power supply circuit for laser device. It is low cost circuit and very easy to built. This power supply can be built with common parts, most of which you probably already have in your junk box. The secret of this circuit is the transformer used. It is a common 9V 1A transformer unit, connected backwards for step up. Please note that some people may have trouble with this supply. This is due to the slight difference in transformers.

Parts List:

R1 = 10 Ohm 10W Or Greater Resistor
R2 = Ballast Resistor, read the notes
D1, D2, D3 = 1N4007 Silicon Diode
C1, C2, C3 = 0.1 uF / 2000V Capacitor
T1 = 9V 1A Transformer
S1 = 115V 2A SPST Switch
MISC = Case, Wire, Binding Posts (for output), Line Cord

Circuit Notes:

T1 is an ordinary 9V 1A transformer connected backwards for step up.
R1 MUST be installed on a LARGE heatsink. A good heatsink is the metal case the power supply is built in.
R2 secures the laser tube from excess current. It should be soldered directly to the anode terminal on the tube. To find R2, start with a 500K 10W resistor and work down until the tube lights and remains stable.
If you have trouble with the tube not starting easily, use a longer anode lead that is wrapped around the tube.
Depending on the transformer you use, the circuit may or may not work. Build at your own risk. Some transformers consist of very few secondary windings which will quickly saturate the core and basically act like a direct short. The more secondary windings (that is, primary in this circuit) the better.

Simple power supply circuit for laser, source page: http://www.aaroncake.net/circuits/lasersup.asp

Regulated Current Booster for Power Supply

2012-01-02T16:11:00.000-08:00

This is the regulated current booster designed to increase the DC current of a power supply.

Even though the 78xx series of voltage regulators are readily available with diverse current outputs, you could increase the obtainable current output with this circuit. A power transistor is utilized to provide additional current for the load the regulator, preserving a continuous voltage. Currents as much as 650mA will flow by way of the regulator, above this value along with the power transistor will start out to conduct, supplying the additional existing for the load. This needs to be on an sufficient heat sink as it is actually most likely to obtain rather hot. Suppose you use a 12V regulator, LM7812. The input voltage must be a number of volts greater to permit for voltage drops. Assume 20 Volts. Lets also assume that the load will draw 5 amps. The power dissipation within the transistor will likely be Vce * Ic or (20-12)*8 = 40 Watt. It may possibly preserve you warm within the Winter, but you might have to have a big heatsink with very good thermal dissipation.

If you would like to enhance the output current using a negative regulator, just like the 79xx series, then the circuit is comparable, but an NPN type power transistor is applied as a substitute.

Variable DC Power Supply 3-24V / 3A

2011-12-26T03:48:00.000-08:00

This is the variable DC power supply circuit. This power supply has regulated output, can be adjusted from 3 to 25 volts and the current output is limited to 2 amps as shown, however it may possibly be improved up to 3 amps or more by applying a smaller current sense resistor (0.3 ohm). Voltage regulation is controlled by 1/2 of a 1558 or 1458 op-amp. The 1458 may be substituted in the circuit, but it is suggested the supply voltage to pin 8 be limited to 30 VDC, which can be achieved by adding a 6.2 volt zener or 5.1 K resistor in series with pin 8. The 2N3055 and 2N3053 transistors need to be attached on proper heatsinks and the current sense resistor must be rated at 3 watts minimum.

The maximum DC supply voltage for the 1458 and 1558 is 36 and 44 respectively. The power transformer ought to be capable of the preferred current while keeping an input voltage at least 4 volts higher than the expected output, but not surpassing the maximum supply voltage of the op-amp under minimal load conditions. The power transformer shown is a center tapped 25.2 volt AC / 2 amp unit that will deliver regulated outputs of 24 volts at 0.7 amps, 15 volts at 2 amps, or 6 volts at 3 amps. The 3 amp output is acquired utilizing the center tap of the transformer with the switch in the 18 volt position. All components/parts should be available at Radio Shack with the exception of the 1558 operational amplifier.

Variable DC power supply 3-24V / 3A circuit source page: www.bowdenshobbycircuits.info

600V Power Supply for QRO HF Amplifiers

2011-12-19T00:40:00.000-08:00

Here the schematic design diagram of 600V power supply for QRO HF amplifiers. Amateur Radio Transmitters working with valves such as 807 or1625 operates properly using a plate voltage in between 600V to 700 Volts. The circuit described below is actually a full wave voltage doubler. The output voltage is twice the input voltage. For 230V AC input the output is going to be close to 600 Volts.

Resister R1 is applied to minimize the initial high voltage and high currents. Capacitor C1, C2, C3 along with coils L1 and L2 form input line filter. The capacitors C4 and C5 protects diodes from high voltage transients on the AC line as well as minimizes inter carrier hum modulation of the R.F picked up by the mains. Capacitors C6 and C7 gives sufficient filtering for the output DC Voltage.

Parts List:

C1, C2, C3 = 0.1 mf 630V
C4, C5 = 0.01 mf 630V
C6, C7 = 100 mf 450V
R1 = 10E 5W Wire Wound
R2, R3 = 220KE 2Watts
D1, D2 = BY127
D3, D4 = BY127
L1, L2 = 12 Turns 18 SWG, Wound over 4 Cm, long Ferrite Rode.

600V power supply for QRO HF amplifiers, circuit source:
http://www.flashwebhost.com/circuit/600_volt_power_supply.php

DC Short Circuit Protection with Electronic Fuse

2011-11-23T13:59:00.001-08:00

Here the diagram of electronic fuse circuit. This circuit will help to protect the load against short circuit for DC circuit application. Relays should be chosen with a voltage value equals to the input voltage. Do not omit making use of the 100uF capacitor with proper voltage value with respect to the input voltage. The circuit use Silicon Controlled Rectifier (SCR) BRX46 which is designed for control systems and sensing circuit applications. In case you cannot find this component, it is possible to use C106 as a substitute of BRX46.

It is possible to alter the electric current with applying 10K potentiometer. In the event you will utilize the fuse with very high currents, then reduce the 0R6 5W resistor value (ex. 0R47, 0R33, 0R22 or 0R1). Watt value of the resistor also needs to be increased also.

Discharge Indicator Circuit for 12V Lead Acid Battery

2011-11-12T03:25:00.001-08:00

Here the discharge indicator circuit for Lead Acid battery 12V. This circuit is used to prevent the batteries from damage. When discharging the battery voltage pin 12V Lead may not be reduced below 10.8V, so we notice the lighting of Led, when the voltage falls below this value. To achieve control we need a constant voltage and a circuit that can compare this with the controlled voltage. And these two conditions to ensure the IC1-LM 723.

The input terminals of the circuit connected to the battery terminals. In IC1/6 shows a steady trend of +7.15 V, when the input voltage is greater than + 9.5V. The constant voltage is applied to IC1/5. In IC1/4 applies a voltage of the input, controlled by the trimmer TR1. The IC1 is act as voltage comparator . So when the voltage at IC1/4 is greater than the voltage at IC1/5, then the output of IC1/9, is low [L], the Q1 is off and the LED is off. To turn the LED should the voltage at IC1/4 be less than the reference voltage at IC1/6, where the output of IC1/9 will be high [H], the Q1 conducts and LED lights.

To configure the circuit will need an external power supply, which will be configured to output a +10.8 V, we apply the input circuit. Adjust the trimmer TR1, so that lights the LED, with no decrease in the voltage of power supply. The input terminals of the circuit should be connected directly to the battery terminals and may be used when using batteries 12V (Lead Acid).

Split Power Supply Circuit 22V DC

2011-11-02T03:04:00.000-07:00

This is the circuit diagram of split power supply circuit which will give a regulated DC voltage (+)22V ; GND and (-)22V. This is an old regulated power supply design which built using active components of dioda zeners and transistors to give regulated output.

This is a very basic voltage regulator circuit, without any additional features such as foldback current limiting, and doesn't have the same performance as an IC regulator such as 78xx series.

Variable Lab Power Supply 0-24V / 4A

2011-10-26T14:36:00.000-07:00

Variable lab power supply 0-24V / 4A, it is a laboratory power supply with output voltage continuously adjustable from 0 V to 24 V DC, remote voltage sense capability (Sense internal/external). It has output current limit which is continuously adjustable from 0.04 A to 4 A and output current which can be limited continuously or output shut down (Limit/cut).

Remote sensing means that there are actually two extra wires which sense the delivered voltage at the load and compensate for any voltage drop along the cables which carry the delivered electric current. This improves voltage regulation at the load significantly but needs two extra wires for the sensing. A switch will allow internal sensing at the output terminals for easier operation when remote sensing isn't necessary.

Read the detailed explanation about Variable Lab Power Supply 0-24V / 4A

Variable Power Supply Circuit 3-24V / 2A

2011-10-23T14:44:00.000-07:00

This the variable power supply with regulated output. The circuit can be altered from 3V to 25V and the electric current is limited to 2 amps as shown. But it's possible to be increased to 3 amps or more by applying a smaller current sense resistor (0.3 ohm).

The power transistor 2N3055 and 2N3053 is used to boost the output current and it should be mounted on suitable heat sinks and the current sense resistor should be rated at 3 watts or more.

2000V High Voltage Low Current Power Supply

2011-09-26T00:46:00.000-07:00

This is a high voltage, low current power supply circuit which will give you high power voltage about 2000V output from 15VDC input.

A high voltage power supply can be a really beneficial source which could be properly utilized in a lot of applications like biasing of gas-discharge tubes and radiation detectors and so on. Such a power supply could also be utilized for protection of property by electric charging of fences. Here the electric current requirement is of the order of several microamps. In such an application, high voltage would basically exist in between a ‘live’ wire and ground. When this ‘live’ wire is touched, the discharge starts through body resistance and it provides a non-lethal but deterrent shock to an intruder. The circuit is built around a single transistorised blocking oscillator. An vital element in this circuit could be the transformer. It could be fabricated on quite easily available ferrite cores. Two ‘E’ sections of the core are joined face-to-face after the enamelled copper wire wound on former is placed in it.

Here the transistor winding:

2000V High Voltage Low Current Power Supply Source:
http://www.electronicsforu.com/efylinux/circuit/cir96.htm