Wednesday 4 February 2015
High Power Pulse Generator using LM350T and NE555
This is a high power pulse generator circuit, Which have main
components are IC555 as oscillator and LM350T provided high current up
to 3A max.
When you see in Simple Pulse Generator May will has a question or like to want the high current output. Which normall current of 200mA maximum only. Today we will tell to you, can increate current output up to 3A.
In first time, we think to use the power transistor-2N3055 (popular part in all time) to add up. But we can use other way use IC-LM350T which is DC regulator 3A IC.
In the figure below we still to use the NE555 as the integrated circuit to generat out to a Square wave Oscillator. Which we can adjust the frequency output with rotate a VR1-100K. Then a signal is send to output pin go to the predrive transistor-2N2222 to control give adj pin of IC LM350T works. While there voltage come to output is the character as high power pulse that current tall about 3A.
So friends changes value of R5 for control the level voltage output in minimum 1.25V to high voltage at around 15V, because of this circuit uses input (voltage of power supply about 5V – 15V)
The other ideals, if you want current just only 1A output current, you can use LM317T that it is cheaper than LM350T.
When you see in Simple Pulse Generator May will has a question or like to want the high current output. Which normall current of 200mA maximum only. Today we will tell to you, can increate current output up to 3A.
In first time, we think to use the power transistor-2N3055 (popular part in all time) to add up. But we can use other way use IC-LM350T which is DC regulator 3A IC.
In the figure below we still to use the NE555 as the integrated circuit to generat out to a Square wave Oscillator. Which we can adjust the frequency output with rotate a VR1-100K. Then a signal is send to output pin go to the predrive transistor-2N2222 to control give adj pin of IC LM350T works. While there voltage come to output is the character as high power pulse that current tall about 3A.
So friends changes value of R5 for control the level voltage output in minimum 1.25V to high voltage at around 15V, because of this circuit uses input (voltage of power supply about 5V – 15V)
The other ideals, if you want current just only 1A output current, you can use LM317T that it is cheaper than LM350T.
Tuesday 15 April 2014
AF Amplifier With Digital Volume Control Based On TDA8551
The Philips Semiconductors TDA8551 is a small audio amplifier with an integrated volume control. When operated from +5 V, it delivers a nominal output power of more than one watt into 8 ohms. It can also be used over a supply voltage range of +2.7 to +5.5 V, with correspondingly reduced output power. The output volume can be adjusted from –60 dB to +20 dB in 64 steps, using a set of up and down push-buttons. The shared UP/DOWN input for the up and down switches has three states. If it is ‘floating’, which means that both of the switches are open, the volume remains unchanged. A pulse to earth decreases the volume by 1.25 dB, while a positive pulse increases the volume by 1.25 dB.
When the power is switched on, the internal counter takes on the –20 dB setting. An additional input (MODE) allows the amplifier to be switched from the operating state to the mute or standby state. If this input is held at the earth level, the amplifier is operational. If +5 V is applied to this pin, the TDA8551 enters the Standby mode, in which the current consumption drops from the typical operational level of 6mA to less than 10µA. Finally, the MODE input can be used as a mute input by applying a voltage of 1 t0 3.6 V to this input. This voltage can be provided by a connection to the SCR pin, which lies at half of the operating voltage and to which a filter capacitor is connected.
The loudspeaker is connected in a floating configuration between the two outputs of the bridge amplifier in the TDA8551. This provides the desired output power level, in spite of the low supply voltage. For headphone applications, which do not need as much output power, you can connect the headphone between earth and one of the outputs, via an electrolytic coupling capacitor. You can make a stereo headphone amplifier in this way, using two TDS8551 ICs. The TDA8551 is housed in a DIP8 package. The SMD version is the TDA8551T, in an SO8 package.
Digital Volume Control
With this circuit you can make the amplifier volume control without
having to use a potentiometer, but using a circuit with IC DS1669. For
working voltage of the IC of this type was not 5 volts, but 4.5 VOLTS to
8 Volt, but used in this circuit at 5 V because it is more secure than
the IC find that you are using exploded.
And the market is a lot of series this circuit of ICs such as:
- DS1669-10
- DS1669-50
- DS1669-100
Number after the hyphen that explains the resistance value of the IC,
such as the DS1669-50 means that this ic 50K ohm resistance.
For the datasheet of this IC you can see below.
Pin Description IC DS1669
- RH - High Terminal of Potentiometer
- RW - Wiper Terminal of Potentiometer
- RL - Low Terminal of Potentiometer
- -V, +V - Voltage Inputs
- UC - Up Contact Input
- D - Digital Input
- DC - Down Contact Input
Standard resistance values IC DS1669
- DS1669-10 ~ 10 kΩ
- DS1669-50 ~ 50 kΩ
- DS1669-100 ~ 100 kΩ
Tuesday 8 April 2014
How to make home made solar pannel
Solar Panel Build
Posted: October 3, 2011 | Author: ericbarch | Filed under: Projects |1 Comment Make sure to read both the Wind Turbine Build and the Solar Panel Build. Then watch The Tech Junkies Episode #9 that documents it all and puts them to the test!Solar has really come down in price since the last time I looked. We wondered if we could start powering our shop off of solar. A good project would be to see if we can build a small scale solar array which would generate power back to the shop and keep it under $1/watt. This would have to include everything from the solar cells to getting usable power out the other end. So we started searching around.
Solar Cell Selection
We went to our favorite buying spot (eBay) and did some looking around to see how much we could find some solar cells for. We found that there are production error cells out there that have some blemishes or chipped edges and you can pick these up for dirt cheap….about 25 cents a watt. So we grabbed 2KG worth (they sell them by weight) which will allow us to make about a 500 watt array. The cells are 3.25″x6″ and are VERY FRAGILE! Who knew these things would break if you breathe on them too hard. They are 0.5 VDC with a maximum 3.6 Ampere output meaning they have a max output of 1.8 watts. Since some of them are chipped or blemished we need to figure we will get less than perfect output from them.
Solar Panel Size and Voltage Choice
We had 9 of the same old windows laying around the shop and they would work really good for about a 50 watt panel each. Wired together they should make a 450 watt array. Really any window panel size will do. Since we are making this on a budget, free windows will definitely help. Making common voltage solar panels helps in wiring them together so they are all working equally. You will lose some voltage from the diode that has to be installed on each panel, but shoot for 12, 18, 24, or 48 volt output panels or arrays.
Electrical Grid Tie Inverter Selection
What exactly is a Grid Tie Inverter and why is that what we want to use? It connects to your existing household AC outlet on on side, and your wind turbine on the other. It converts the DC wind power to an AC pure sine-wave matching the phase of the grid. Since the electricity is being generated on the house side of the power meter, the generated power will actually slow down your power meter or bring it to a stop. But if you are lucky enough to have an old dial turning style power meter AND are generating more power than you are using, it is possible to spin your electrical meter BACKWARDS! I didn’t believe it either until we tried it and it worked.Grid tie inverters have come down in price and gotten pretty good recently. We expected to pay about 25 cents per watt in this part of the build. They are usually stackable too, which means as your system grows, you can just add another grid tie inverter and they will all just work in tandem.
This is the grid tie inverter we got. It was $138 (27.6 cents per watt) and again we sourced this from eBay.
Assembly and Testing
Here you can see we wired 11 cells in series for each row (5.5VDC). The cells vary voltage from top to bottom and vary current side to side. Meaning if you broke a cell in half 3×3 you would still measure full voltage and have half the amp output. We made 2 full rows, and a third row of cells we broke in half like we just mentioned. Edit: As pointed out by Hack a Day commenter Mark, we effectively limited the current of the entire panel by doing this. This can also lead to overheating in the half panels. At the time, our main concern was getting the voltage high enough for the inverter. For the next set of panels we will be using only full cells. So 3 rows of 5.5VDC = 16.5VDC, then minus the diode voltage drop and we should see around 15-17 Volts Output in operation. We plan on putting 3 panels in series and each series in parallel making a 45-51 Volt (or 48V standard) array.
It makes it easier if you pre-wire a lot of cells before you start. Here you can see we started making piles of them. It really goes quick and is pretty easy to get the hang of once you do a few. The trick is to get a soldering iron that can get hot enough to make it so you don’t have to spend a lot of time on any part of the panel for too long. It took us a few hours to build a 50 watt panel. That time involved will play a part in how big of a system you want to start with.
The cells get wired together easily by running “tabbing” wire down them after applying a flux pen. This make soldering to the solar cells painfully easy. Here you can see all 33 cells wired in series. With each full 3×6 cell theoretically capable of producing 1.8 watts and the halves at 0.9 watts this would be a maximum of 49.5 watts. We’ll round and call this a 50 watt panel.
Once all the cells are wired in place, we tape everything down and give it one last electrical test. This will temporarily hold it in place while we pour a two part polyester resin epoxy over it all to lock it in place.
Here is the epoxy sitting to harden up. When we made this we used old epoxy in cool temps and it came back to bite us. Ours peeled up and ended up taking so long to set up that it leaked through our masking tape and got under some of our panels. We figure we now need fresh epoxy and use about 1/10th of a gallon or less for this size panel. A little goes a long way and really this is just to give it a thin seal and lock everything in place.
Results and Thoughts
Here is the breakdown of our costs:$125 Solar 3×6 cells creating 500 watts worth
$0 Windows
$50 Gallon of Epoxy
$25~$50 Tabbing wire and diodes
$138 Grid Tie Inverter
————-
So for roughly $375 we have built a Solar Array capable of producing 35-50 watts in it’s current state, with a maximum of 450 watts if we can get full sun. If we did this again we could get the price down even lower, but for about 75 cents per watt it would only take a few years for us to pay this system off.
The next step on this project is to finish the rest of the panels and tie them all in together and see some long term power generation to get an average for a year. Our first panel puts out about 35 watts in full sun, so we have some improvements to do for the next one.
Let the government pay for 30% of your alternative energy generation project!
As we were digging around with this project I want to make you aware that there are some really good government grants (AS IN FREE MONEY!!!) for those that take advantage of them. As always consult with a professional before deciding to spend any money and never take my word for it. But for what it is worth this website has a lot of good information about getting financial assistance in building alternative energy sources. Check out http://www.dsireusa.org/ to find out if your state has any local policies. As of the writing of this, as long as you START your build before the end of 2011 the Feds will pay for 30% of your project if it is under a commercial business. There are LOTS of grants and loan programs out there to help pay for the costs of installing these systems and now seems like a great time to do it. Earth will love you for it too.Wednesday 19 March 2014
Automatic Parking Light Switch Circuit
This automatic park light switch with LDR automatically turn ON the
light when the surrounding light dims to a preset level. The first
circuit diagram is an NPN design intended for negative grounded chassis.
The second diagram is the PNP version intended for a positive grounded
chasis.
The dim level at which the circuit activates is set through the potentiometer P1.
The printed circuit board layout can be used for both the negative and positive polarity chassis. Take note that the transistors and different for each chassis type. The connectors labeled in the parts placement diagram have the following connections:
P = Power live of the car
C = Car chassis
B = Park light bulb
Parts Placement
Printed Circuit Board Layout
The dim level at which the circuit activates is set through the potentiometer P1.
The printed circuit board layout can be used for both the negative and positive polarity chassis. Take note that the transistors and different for each chassis type. The connectors labeled in the parts placement diagram have the following connections:
P = Power live of the car
C = Car chassis
B = Park light bulb
Automatic Park Light Switch Positive Ground
Automatic Park Light Switch Negative Ground
Parts Placement
Printed Circuit Board Layout
Friday 28 February 2014
Hi-Fi AUDIO POWER AMPLIFIERS
Small stereo amplifier project for computer
you want will build a Small stereo amplifier project for computer. This projects is best for you. Before read detail of they we should read mono model on This is Super Small Power Amplifier BCL 1.2W by TDA7052. If you are seeking the circuit amplifies small-sized. I begs for to advise this circuit because tiny economize with the equipment is a little.This is Super Small Power Amplifier BCL 1.2W by TDA7052. If you are seeking the circuit amplifies small-sized. I begs for to advise this circuit because tiny economize with the equipment is a little. And still can use force against large-sized get comfortablely ( I has tried already ) besides it still use volt power supply very wide be about 1.5V arrive at 15V as well. Regard as IC TDA7052 be worthwhile very much. For you who want to try build this circuit. I has model PCB give a friend tests to see with. Request have fun the circuit amplifies miniature please.
Circuit of Power Amplifier Super Small BCL 1.2W by IC TDA7052
PCB Power Amplifier Super Small BCL 1.2W by IC TDA7052
TDA 2050 Aamplifier
If you want to build hi-fi power amplifier the size about 30watt to 50Watt at good sound and build easy. I begs for to advise the circuit that builds with the integrated circuit. You wares IC TDA2050 then like very the circuit model class AB audio amplifier.
Thanks to its high power capability the TDA2050 is able to provide up to
35W true rms power into speaker 4 ohm load at THD =10%, VS =±18V, f = 1KHz and up to 32W into
8ohm load @THD = 10%, VS = 22V, f = 1KHz.Moreover, the TDA 2050 delivers typically 50W
music power into 4 ohm load over 1 sec at VS=22.5V, f = 1KHz
May take an interest want to try build already, try out this circuit use voltage Vcc +/- 25V.
Part
C1-0,47-22mF
C2-22mF
C3C4-100nF
C5-100(150)nF
R1R3-47kO
R2-1-3,3kO
R4-1-4,7oM/0,25W
Rt-4oM
PCB : 35W Hi-Fi AUDIO POWER AMPLIFIER by TDA2050
on PCB : 35W Hi-Fi AUDIO POWER AMPLIFIER by TDA2050
Mini 40 watt audio car amplifiers using HA13001
From this 20watt Integrated Amplifier project. Some people say that expensive and want the main amplifier only. I recommend this project, it had a budget of only 5$. and is the main amplifier. They have size of power to speaker is 40 watts and use voltage of power supply is 12 volts so can apply right in car. They use the HA13001-IC is key parts so small and build easily.How This Circuit works
When see a circuit as Figure 1 Many people would doubt that. This circuit will be amplified up to 40 watts. (If as the RMS will is about 17.5 watts at load 4 ohms). You do not insult it because the many circuits that were contained in IC1-HA13001 of Hitachi there. Makes a few external devices, and the output of IC1 that connects to the loud speaker will be connected on the bridge circuit types. So causes the output has a high power there.
Figure 1 the circuits use IC-HA13001
We do not fear that the speaker will be damaged easily. because in IC1 has the Automatic Shut-Off circuit (ASO) that use to protect the speaker. Thus You need to carefree it. and this circuit will use the power supply range between about 12-18 volts for its’ source.
How to builds this projects
This simple project starting with make the PCB which has copper layout as figure 2 before. Then solder all components as figure 3. We can solder directly the IC1 onto PCB so should take special care.
Figure 2 The PCB layout
Figure 3 The components layout for PCB
The power supply that can use a DC adapter but must provide current over up 1 amperes. Otherwise, when you accelerate the more volume, the sound will be broken and Adapter will malfunction.
The application this projects
This amplifier project use to amplify from the various sound generator such as The iPad or mobile phone or notebook computer’s etc. Or Modified into the old car stereo that repair difficult. We changed the set to the amplifier.
The detial parts.
The electrolytic capacitors 16 volts
C1_________________1uF
C4, C5, C7, C8_______100uF
C6_________________47uF
C11________________2,200uF
The ceramic capacitors 50V
C2_________________0.001uF
C3, C9, C10__________0.1uF
IC1_number__________HA13001
¼ W + 5% Resistors
R1__________________1K
R2, R3_______________2.2 ohms
Speaker 20 W 4 ohms
Heat sink for IC1
High Current Voltage Regulation
Voltage regulators are available as easy to use three terminal
integrated circuits - one terminal for the input voltage, one for the
output voltage, and one for the ground (0V). The most commonly used are
from the 78XX series - 7812 for 12 Volts, and 7805 for 5 Volts etc. Also of particular use for renewable energy generators are very efficient low dropout regulators such as the LM2940 series - LM2940CT-12 for 12 Volt etc.
One common shortfall of these common regulators is they are rated at just 1 Amp output current. It is usually possible to use them with higher currents, but a large heatsink and/or fan is essential. Regulators for higher currents than 1 Amp are available, but tend to be expensive, and still require good heatsinking.
Pictured above is a circuit from the Fairchild LM7812 datasheet. This uses a power transistor and a power resistor to take on some of the workload enabling higher currents to be regulated. With this set up, the power transistor and power resistor need heatsinking, and selecting the correct specification of transistor and resistor, and getting everything set up is not particularly easy.
One alternative is instead to parallel connect multiple three terminal regulators, with each regulator handling up to 1 Amp of current.
This tiny difference in voltage has the disastrous consequence of making the regulator with the lowest output voltage trying to carry all of the current. This will cause it's internal thermal protection to trigger (as the regulator overheats) effectively removing that regulator from the circuit and kicking off a chain reaction up through the remaining parallel-connected regulators.
The circuit shown above* (from the EDN article High-Current Supply uses Standard Three-terminal Regulator) has two LM7812 voltage regulators connected in parallel for a maximum total output current of 2 Amps - double the rated current of one LM7812.
* Diodes D1, D2, and D should be 1N4007 according to the EDN article, but common 1N4001 diodes will be fine as they are rated up to 50V which is more than enough. The capacitors are supposed to be C=47,000uF, C1 and C2 are 4,700uF, but as a 47,000uF capactitor is expensive and physically very large we tested this regulator using a 4,700uF for C, and 1,000uF for C1 and C2 and had no problems.
An even simpler way to parallel connect multiple voltage regulators together is to add very low (below 1 Ohm) ballast/equalising resistors in series with the regulator outputs. Doing so should make the regulators share current equally and therefore operate together without problems. It is worth noting however that this approach to load balancing makes the voltage regulation a bit less accurate.
An example of this simplistic approach in use can be seen in the above experimental 12V 6A power supply* in which six LM7812 regulators were connected in parallel with 0.25 Ohm load balancing resistors (made up of four 1 Ohm resistors in parallel) connected in series with the output from each 7812 regulator. The schematic shows the key elements in this 6 Amp 12 Volt regulator.
* The original circuit diagram was published on the Wroclaw University of Technology website back when we first published this article in 2006/7. Unfortunately that article is no longer online.
While the LM317T for example is limited to a continuous output of 1-1.5A subject to sufficient heatsinking, one or more power transistors can be added as shown above to make an adjustable high current power supply. Click here for full details: LM317 Adjustable Power Supply.
rrent.
One common shortfall of these common regulators is they are rated at just 1 Amp output current. It is usually possible to use them with higher currents, but a large heatsink and/or fan is essential. Regulators for higher currents than 1 Amp are available, but tend to be expensive, and still require good heatsinking.
Pictured above is a circuit from the Fairchild LM7812 datasheet. This uses a power transistor and a power resistor to take on some of the workload enabling higher currents to be regulated. With this set up, the power transistor and power resistor need heatsinking, and selecting the correct specification of transistor and resistor, and getting everything set up is not particularly easy.
One alternative is instead to parallel connect multiple three terminal regulators, with each regulator handling up to 1 Amp of current.
Parallel Connecting Mulitple Voltage Regulators
Voltage regulators such as the LM7812 cannot just be connected in parallel without additional circuitry. Each voltage regulator, though nominally rated at the same voltage, will in practice output a slightly different voltage - for example, three LM7812's could output 11.98, 12.01, and 12.06 respectively.This tiny difference in voltage has the disastrous consequence of making the regulator with the lowest output voltage trying to carry all of the current. This will cause it's internal thermal protection to trigger (as the regulator overheats) effectively removing that regulator from the circuit and kicking off a chain reaction up through the remaining parallel-connected regulators.
The circuit shown above* (from the EDN article High-Current Supply uses Standard Three-terminal Regulator) has two LM7812 voltage regulators connected in parallel for a maximum total output current of 2 Amps - double the rated current of one LM7812.
* Diodes D1, D2, and D should be 1N4007 according to the EDN article, but common 1N4001 diodes will be fine as they are rated up to 50V which is more than enough. The capacitors are supposed to be C=47,000uF, C1 and C2 are 4,700uF, but as a 47,000uF capactitor is expensive and physically very large we tested this regulator using a 4,700uF for C, and 1,000uF for C1 and C2 and had no problems.
An even simpler way to parallel connect multiple voltage regulators together is to add very low (below 1 Ohm) ballast/equalising resistors in series with the regulator outputs. Doing so should make the regulators share current equally and therefore operate together without problems. It is worth noting however that this approach to load balancing makes the voltage regulation a bit less accurate.
An example of this simplistic approach in use can be seen in the above experimental 12V 6A power supply* in which six LM7812 regulators were connected in parallel with 0.25 Ohm load balancing resistors (made up of four 1 Ohm resistors in parallel) connected in series with the output from each 7812 regulator. The schematic shows the key elements in this 6 Amp 12 Volt regulator.
* The original circuit diagram was published on the Wroclaw University of Technology website back when we first published this article in 2006/7. Unfortunately that article is no longer online.
High Current Variable Voltage Regulation
Where you need to have a user variable voltage output, the LM317 is an excellent adjustable voltage regulator to use. The output voltage is adjusted using a couple of resistors, and one of these resistors can be replaced with a potentiometer to give an adjustable output.While the LM317T for example is limited to a continuous output of 1-1.5A subject to sufficient heatsinking, one or more power transistors can be added as shown above to make an adjustable high current power supply. Click here for full details: LM317 Adjustable Power Supply.
Comment on this Article
If you have any comments on this article, please email them to neil@reuk.co.uk.Hello from Kentucky USA! In regard to this page, I have drawn up a couple of 78xx high current circuits you might like to consider. I've used them for a 30amp power supply with a 7815 regulator. REUK Added Info: The MJE3055 is an NPN silicon power transistor rated at up to 60V, up to 75 Watts, and up to 10 Amps. Click here to view the MJE3055 Datasheet for more information. If you are unable to find the MJE3055, any NPN power transistor with a similar rating can be used instead. Click here to view a selection of NPN power transistors. I have since switched to using the better LM723 regulator so that I can adjust the voltage and it is far more reliable than the 78xx. I have used the LM723 for a 105amp supply. REUK Added Info:The LM723 is a voltage regulator rated for outputs of 150mA at an adjustable voltage from 2V to 37V. By adding transistors as shown in the schematics above high output currents at the regulated voltage can be output. Click here to view the LM723 datasheet. The LM723 is available in the UK from around 30 pence. Click here to buy an LM723 now. I've learned a few things on your site so I thought I'd pass along a little in return. Ken Weaver, 17th August 2009 The benefit of this first schematic is that the output is actually regulated; the PNP is fully in the feedback loop. However in Ken's circuit, the bases of the 3055 are regulated, but not the emitters, where the output is taken. Thus for every current ratio of 2.7 the voltage drops by 25mV. Nick, 10th July 2012 |
Monday 17 February 2014
Adjustable Power Supply with Charger
Circuit :
Notes:
This power supply has adjustable and charger output. The charger circuit can be use for cellular phone. The adjustable output serves as multipurpose power supply. It can handle a 1 ampere current. The 317 must have a heat sink.
PCB Layout:
Parts List:
Semiconductor:
LM 317 - 1pc
LED - 1pc
1N 4001 - 8pcs
Capacitors:
25V/470uF - 1pc
25V/10 uF - 1pc
Resistors:
1k, 1/2W - 1pc
220R, 1/2W - 1pc
5kR Potentiometer - 1pc
Others:
1Ampere, Multi-tap Transformer - 1pc
AC Chord - 1pc
Casing - 1pc
#22 Stranded Wire - 3m
Heatsink for TO220
Notes:
This power supply has adjustable and charger output. The charger circuit can be use for cellular phone. The adjustable output serves as multipurpose power supply. It can handle a 1 ampere current. The 317 must have a heat sink.
PCB Layout:
Parts List:
Semiconductor:
LM 317 - 1pc
LED - 1pc
1N 4001 - 8pcs
Capacitors:
25V/470uF - 1pc
25V/10 uF - 1pc
Resistors:
1k, 1/2W - 1pc
220R, 1/2W - 1pc
5kR Potentiometer - 1pc
Others:
1Ampere, Multi-tap Transformer - 1pc
AC Chord - 1pc
Casing - 1pc
#22 Stranded Wire - 3m
Heatsink for TO220
Nicad Battery Charger
Description:
A basic nicad battery charger using a single medium power transistor.
Notes:
This simple charger uses a single transistor as a constant current
source. The voltage across the pair of 1N4148 diodes biases the base of
the BD140 medium power transistor. The base-emitter voltage of the
transistor and the forward voltage drop across the diodes are relatively
stable. The charging current is approximately 15mA or 45mA with the
switch closed. This suits most 1.5V and 9V rechargeable batteries. The
transformer should have a secondary rating of 12V ac at 0.5amp, the
primary should be 220/240volts for Europe or 120volts ac for North
America.
Warning:
Warning:
Please take care with this circuit. Use a voltmeter to observe correct polarity. Nicads can explode if short circuited or connected with the wrong polarity.
Tuesday 11 February 2014
2WATTS FM TRANSMITTER
USE DIPOLE ANTENNA FOR MAXIMUM RANGE (COULD BE UP TO 10 KM IN GOOD
WEATHER). TUNE BETWEEN 88-108 MHz WITH C5. BB-204 COULD BE REPLACED WITH
CONVENTIONAL LED (BIG) WITH REVERSE BIAS (NO LIGHT GIVEN IN CORRECT
POLARITY). 9V POWER FOR 2KM WITH GOOD SOUND QUALITY AND GRADUALLY UP TO
18V FOR 10 KM RANGE WITH POOR QUALITY OF SOUND. BEST OF LUCK.
High Voltage Converter: 90V From 1.5V
The circuit shows one way of obtaining a voltage of 90V from a 1.5V
battery supply. The LT1073 switching regulator from Linear Technology (http://www.linear-tech.com)
operates in boost mode and can work with an input voltage as low as 1.0
V. The switching transistor, which is hidden behind connections SW1 and
SW2, briefly takes one end of choke L1 to ground. A magnetic field
builds up in the choke, which collapses when the transistor stops
conducting: this produces a current in diode D1 which charges C3. The
diode cascade comprising D1, D2, D3, C2, C3 and C4 multiplies the output
voltage of the regulator by four, the pumping of C2 causing the voltage
developed across C4 via C3, D2 and D3 to rise.
Finally, the regulator control loop is closed via the potential divider (10 MΩ and 24 kΩ). These resistors should be 1 % tolerance metal film types. With the given component values, fast diodes with a reverse voltage of 200 V (for example type MUR120 from On Semiconductor http://www.onsemi.com) and a choke such as the Coilcraft DO1608C-154 (http://www.coilcraft.com) an output voltage of 90 V will be obtained. The output of the circuit can deliver a few milliamps of current.
Finally, the regulator control loop is closed via the potential divider (10 MΩ and 24 kΩ). These resistors should be 1 % tolerance metal film types. With the given component values, fast diodes with a reverse voltage of 200 V (for example type MUR120 from On Semiconductor http://www.onsemi.com) and a choke such as the Coilcraft DO1608C-154 (http://www.coilcraft.com) an output voltage of 90 V will be obtained. The output of the circuit can deliver a few milliamps of current.
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