What Must todo

his might be a good practice project for beginners who just started learning embedded electronics. It is about making a very basic programmable digital timer using a PIC16F628A microcontroller. The timer duration can be set from 0-99 minutes.

As I mentioned earlier, the microcontroller used in this project is PIC16F628A running at 4.0 MHz clock using an external crystal. An HD44780 based 16×2 character LCD is the main display unit of the project where you can watch and set the timer duration using tact switch inputs. There are three tact switches connected to RB0 (Start/Stop), RB1 (Unit), and RB2 (Ten) pins. You can select the timer interval from 0-99 min using Unit and Ten minute switches. The Start/Stop switch is for toggling the timer ON and OFF. When the timer gets ON, a logic high signal appears on the RA3 pin, which can be used to switch on a Relay. The circuit diagram of this project is described below.

When the device is powered ON, the microcontroller initializes the LCD display and shows the following message. The timer is initially OFF and so does the LED or relay, whichever is connected to RA3 pin. You can set time duration between 00-99 min (in step of 1 min) using the Unit and Ten tact switches. Each switch press will increment the corresponding time digit.

When the desired time is set, press the Start/Stop switch to turn ON the timer. The RA3 pin goes high (LED glows) and the count down begins. When the timer is ON, the remaining time is also shown on the LCD screen. When the time elapsed, the timer stops and the LED turns OFF. You can interrupt and stop the timer at anytime by pressing the Start/Stop switch once more. The firmware for PIC is developed using mikroC Pro for PIC compiler. The use of Timers are avoided for simplicity. The time delays are created using the Delay_ms() function of mikroC, which seems to give reasonably accurate timing delays.

Download Mikroc Source Code And HEX File

Overview
The construction of the circuit has been increased to highlight and amplify video signals for further frequencies on image clarity.

Video Signal Amplifier Circuit diagram


Terminology

LH0024 – IC small signal IC designed for general purpose switching and amplification due to its low voltage, low voltage and three different win the election 1N4148 – silicon small signal diode planar epitaxial used for fast switching applications with a reverse voltage of 100 V and forward current of 150 mA

Circuit Explanation

In a video output signal is the high rate of frames selected for amplification of producing a finer. This is possible by placing the track between the video device and the reception lobby, where the video port of the television receiver is inserted. The construction is done simply by exploiting the operation of three transistors instead of IC and other supporting elements.

An isolator operating in the first phase of the Q1, which provides an interface for input impedance. Q2 manage the second phase, which leads to the common base configuration. In this phase, determine the earnings TR2 250 ohms cutting the lawn. To adjust TR2, it must be placed where an output voltage of 1 Vp-p is present, with a load of 75 ohms. The frequency response is regulated by a combination of R6, C3, and 500 ohms TR1. An output buffer is completed by Q3 of the third phase which provides an airline pilot with 75 ohms. The range of the circuit is stabilized with 12 V and 50 mA.

This is a simple LED flasher project that uses a common 555 timer IC for its operation. It is configured as an astable mode which means that its output is a square wave oscillator. Two LEDs are connected to its output in such a way that when one LED is ON, the other LED will turn OFF. 

It uses only 10 simple parts that are easily available at any electronic shops. Capacitor C2 charges exponentially through resistors R1, R2 and the resistance of the trimpot. When C2 has charged to about 2/3 VCC it stops charging and it discharges to about 1/3 VCC through R2 and the trimpot resistance via pin 7. This is the standard operation of a 555 timer. When a Vcc of 5 V to 15 V DC is applied to the circuit, the LED will start to flash.

The frequency of the flashing can be changed by varying the resistance of the potentiometer or trimpot. Parts List The parts list of the simple LED project is as shown below.

A very simple heat detector alarm electronic project can be designed using the UM3561 sound generator circuit and some other common electronic parts . This heat detector electronic circuit project uses a complementary pair comprising npn and pnp transistor to detect heat . Collector of T1 transistor is connected to the base of the T2 transistor , while the collector of T2 transistor is connected to RL1 relay . T3 and T4 transistors connected in darlington configuration are used to amplify the audio signal from the UM3561 ic .

Heat Detector Alarm Circuit diagram

When the temperature close to the T1 transistor is hot , the resistance to the emitter –collector goes low and it starts conducting . In same time T2 transistor conducts , because its base is connected to the collector of T1 transistor and the RL1 relay energized and switches on the siren which produce a fire engine alarm sound . This electronic circuit project must be powered from a 6 volts DC power supply , but the UM3561 IC is powered using a 3 volt zener diode , because the alarm sound require a 3 volts dc power supply . The relay used in this project must be a 6 volt / 100 ohms relay and the speaker must have a 8 ohms load and 1 watt power .

This arrow led indicator electronic project can be used in some dark places to show the directions . You can use to indicate direction just an illuminated arrow or a flashing light , but is much nicer if the light moves in the correct direction.

This arrow led indicator is based on 74HC14 circuit and some LEDs which are used to show the way .
For this arrow led indicator we need six series of three LEDs arranged in the shape of arrows and are connected to the outputs . Each time the lit arrows move over by one column so it appears that the arrows run from right to left.

Arrow LED Indicator Circuit Diagram



If we want to change the speed of the moving light it’s need to change the value of C1 to C3 or R1 to R3 ( a lower value for this components decrease the time of moving lights). If we want a longer arrow we can mount in parallel with existing columns another columns .
For power supply we can use batteries or 6V regulated power supply .

The series of touch this switch be an Touch Switch made ​​using FET. This circuit serves to activate electronic devices only when we touch touch sensors.
Once we release a touch to the sensor, the electronic device that is connected is turned off again. The series of touch switch or touch switch is very simple, composed only of a FET, resistor and capacitor. The series of touch switches / touch switches work with source voltage 12VDC. Detailed series of touch switches / touch switch can be seen in thethe following figure .

FET Touch Switch

The series of touch switches / touch switch can only be used to illuminate DC, 12V DC lamp when it replaced the relay, the circuit can be used safely to load the AC network. Sensor touch to this series was made with 2 pieces of plate are arranged close together (within 1-2mm).

The LT3754 16 channel LED driver with a step-up DC DC controller designed by Linear Technology is capable of driving up to 45V of LEDs. Each channel of the LT3754 led driver contains an accurate current sink with ±2.8% current matching.If are used high current Leds channels can be paralleled.

16 Channel LED Driver Circuit Diagram

Using LM833 can be designed a very simple tone control circuit using few external components .For this Lm833 ton control circuit can be used almost any type of operational amplifier if it have high input impedance .The LM833 is a is a dual general purpose operational amplifier designed with particular emphasis on performance in audio systems.

Tone Control Circuit Diagram



The ton control from this circuit is based on this operational amplifier from National Semiconductor and two RC filters ( low pass and high pass ) .Using the formula presented bellow we can modify the frequency of the tone control circuit - the cut off frequency of RC filters (low pass and high pass )lm833 tone control formula For the tone control circuit presented in this schematic the frequencies are : fL = 32 Hz, fLB = 320 Hz and fH =11 kHz, fHB = 1.1 kHz.

Welcome to free circuit dot com,For the last article in this series, we may be unstable a cycle which has no stable output state. In this post circuit we will show the monostable circuit, which has a stable state.

Basic Monostable Circuit diagram 

The waveforms in Figure 1 show the effect of a monostable. A monostable circuit produces a pulse of a certain length (time T) in response to a trigger input such as a pushbutton. The output of the circuit remains in the low position to a trigger input, does the name “Mono”, “stable condition”. This type of circuit is ideal for use in a “push-to-operate” in a model system for exhibitions.

A visitor can press a button to a model mechanism in motion, and the mechanism will automatically after a certain time. Another use of the circuit “the bounce” an important contribution to a digital IC – this application will be explained later in this article.

A very simple LED driver electronic project can be designed using the CAT3649 high efficiency quad mode R fractional charge pump IC that can drive up to six LEDs. The inclusion of a 1.33x fractional charge pump mode increases the device efficiency by up to 10% over traditional 1.5x charge pumps with no added external capacitors.Low noise input ripple is achieved by operating at a constant switching frequency which allows the use of small external ceramic capacitors. The multi−fractional charge pump supports a wide range of input voltages from 2.4 V to 5.5 V.



The LED current can be adjusted in different ways. The full−scale LED current is set to 25 mA once the device is enabled. Analog dimming in 32 linear steps is achieved via a 1−wire pulse−dimming input (ADIM)
Further adjustment of the LED current can be done by applying a pulse width modulation (PWM) signal on the PWM input.The CAT3649 can be shut down by holding the ADIM or PWM input in a logic low condition for greater than 30 ms. This electronic design CAT3649 charge pump LED driver can be used in applications like : LCD Display Backlight , Cellular Phones , Digital Still Cameras and some other handheld devices .

If the input voltage is insufficient or falls to a level where the regulated currents cannot be maintained, the CAT3649 automatically switches into 1.33x mode. In 1.33x mode, the output voltage is approximately equal to 1.33 times the input supply voltage . This sequence repeats in the 1.33x and 1.5x mode until the driver enters the 2x mode.While in 2x mode, the output is approximately equal to 2 times the input supply voltage.If the CAT3649 charge pump LED driver detects a sufficient input voltage to drive all LED currents in 1x mode, it will change automatically back to 1x mode.

Microcontrollers attend to to take place fanatical to a detail drive, so while theyon the subject of very flexible strategy these days, at hand are a amount of various (often conflicting) options in lieu of how you might need the hardware to handiwork. You might think with the aim of this configuration is complete fashionable software, but could you repeat that? if you want the hardware to proceed a assured way from the very start? Keeping in mind with the intention of C.P.U PIC diplomacy can "riding boot" in a carry some weight of milliseconds, in attendance needs to be present a way you indicative the hardware how to perform in advance of it opening up. This article covers how to understand your microcontroller based project working the way you expect what time it starts up.

Enter config bits, before, seeing that they used to occur called, config fuses. Back inwards the days as soon as microcontrollers were syllabus-as soon as campaign, you really did blow a fuse in order to program them. now, for the most part micros partake of flare recall with the intention of can be planned tens of thousands of period, but in attendance are still single-period-programmable (OTP) procedure all but.

In one court case, nears a bunch of "config terminology" to facilitate describe how the micro is going away to conduct yourself from the induce-stretch. accede tos look by the side of a number of of these options (well select the PIC18F2620 so an model) and therefore perceive how to list them. Sourceboost gives you all the config strings featuring in a standing by-to-utilize format on behalf of together with in your project. The format has the config bits suffixed with the same famous person as the config word so you can ensure with the purpose of the accurately bits are departure in the right word. Of course of action, your config language yearn for survive discrete if youon the subject of using a different microcontroller, but you be supposed to study as much as necessary at this time to promontory you during the right direction.

In the 18F2620, the config bits are stored in twinkle, but next to a great recall location. Theya propos stored on 0x300001 and upwards. intended for historical reasons due to the way remembrance was previously arranged on PIC microcontrollers, config expressions are numbered with every add up to having a "high" and "low" byte.

CONFIG1L doesnt exist on the 18F2620. If it did, it would live by 0x300000 location.

CONFIG1H contains bits so as to spell out oscillator options. commonly, into Embedded Adventures projects we try and value peripheral crystals which offer supplementary accurate and steadfast results. This does use up two pins however, and on occasion these can subsist new essential than the hurry by which the disfigure is running. The outdoor gemstone oscillator is referred to in the function of the HS oscillator (if youpertaining to responsibility the classic obsession of frustrating to run the micro as fast as it want get to). into the 18F2620, you can too enable the PLL module which will allot you a four-epoch break the speed limit boost. From CONFIG1H are besides options to enable the fail-safe control screen (with the purpose of switches to the domestic oscillator be supposed to the outer solitary fail, and an option to enable the switching among atypical oscillator sources.

We usually advise with the purpose of you utilization an peripheral rock, and roll inedible one oscillator switching / failover modes. arrived prototyping, it is weighty to partake of steadfast, repeatable results (mostly so you can reduce the axes of miscalculation). It is probable to configure the 18F2620 to start up using the interior oscillator (which runs by 8Mhz, otherwise 32Mhz with the PLL enabled) and subsequently switch to the outside lone (we use a 10Mhz sparkler with PLL enabled giving you 40Mhz). with the aim of gives you nearer startup from interrupts featuring in nap mode before on bootup, if thats valuable, however in support of prototyping, this is normally not essential.

Our recommended config row for CONFIG1H:

#pragma DATA _CONFIG1H, _OSC_HSPLL_1H & _IESO_inedible_1H & _FCMEN_OFF_1H

CONFIG2L handles bronzed-exposed reset and the power up timer. Brown Out Reset (or else BOR) is the talent on behalf of the microcontroller to reset itself if the supply voltage cascade under a specified threshold. It self-control wait all the rage reset state until the supply goes back completed the threshold. This can mean a number of battery saving (on slightest, formerly the battery is preset ahead of a selected level, itll be over draining power in the role of quickly) - but on with the intention of use presents veto functionality open anyway. The power on timer waits on first power-on used for the supply to travel more than the BOR voltage threshold, at that moment hangs around for an additional 65ms in advance kicking things rotten for real. This can help ensure with the aim of your power supply is steady before annoying to accomplish several code.

We grasp seen around pretty unpredictable results from the 18F2620 while tough some LED put on show panels. We concept the software was rolling or else resetting the micro while stylish information, could you repeat that? was event was the BOR was being tripped to the same extent additional LEDs were lit and the power supply dropped. As such, but for youve got a real need in support of it, we advise switching it inedible. Leaving the power supply to settle formerly preliminary the firmware, is by and large a satisfactory suggestion (yourelating to probably not disappearing to notice the 65ms it takes).

#pragma DATA _CONFIG2L, _BOREN_inedible_2L & _BORV_2_2L & _PWRT_ON_2L

CONFIG2H gives you settings used for the watchdog timer. This is a timer with the purpose of resets the PIC in the sphere of a precise amount of occasion (you can broadly detail how slow that might transpire). It might be good chart to reset your PIC if youabout burden something from which you might on no account recover - although confidently youre in print good a sufficient amount code with the aim of this cannot go off! on the other hand, the watchdog timer can as well tug the PIC shown of have a lie-down mode. This channel you can display in favor of the PIC to operate to sleep for a several amount of phase (if nothing as well happens). For prototyping, we advise switching the watchdog timer rotten. If you figure out enable it, make up certainly you reset the watchdog timer steadily before - well, you can deduction I beg your pardon? force transpire.

#pragma DATA _CONFIG2H, _WDT_sour_2H & _WDTPS_128_2H

CONFIG3H has a collection of configuration items. You can point out intended for the RE3 pin to exist open (when input merely) before for with the intention of pin to be MCLR (which resets the micro as soon as pulled low). For prototyping, being able to reset the micro by critical a button is easier than pulling the power ready.

The LPT1OSC tad gives the option of a "area of high pressure power" mode or else a "low power mode". The low power mode is supplementary delicate happening high blare environments. So if battery practice is very essential, you need to design your circuit carefully. representing prototyping, of pattern, we would vouch for leaving this in high power mode.

PBABEN, allows you to list if PORTB pins 0 - 4 be supposed to wake up what analog input pins or else digital pins in the lead reset. Of course you can adjust this popular software in the ADCON1 register on a few calculate.

The CCP module is a Capture / Compare / PWM module and a final CONFIG3H fragment allows the "steering" of this output to ensue on either RC1 before RB3. This is within reach to be able to change if you require the other functionality open on solitary of these pins (RB3 is besides analogue input 9 and RC1 can be Timer 1 oscillator input). on the other hand, your PCB arrangement might happen easier if you may well move this output to lone before the other. instead of prototyping, in the main this doesnt problem either way.

#pragma DATA _CONFIG3H, _CCP2MX_PORTC_3H & _PBADEN_inedible_3H & _MCLRE_ON_3H

CONFIG4L contains various appealing options and shows very openly how worthy it is to ensue able to configure the PIC already startup.

The DEBUG smidgen allows hardware debugging. You can step through code, stage set breakpoints and so on - if you get your software set right and this tad unfurnished. Hardware debugging and requires the exclusive advantage of RB6 and RB7 (also used in place of ICSP brainwashing). now all honesty, we uncover to ongoing output is in general sufficient to find bugs, although you can debug a batch of PICs with just a PicKit2.

XINST allows for the 18F extended education set mode. This isnt used by Sourceboost and if you switch it on by underestimate (despite the consequences of the compiler youon the subject of using) near desire be alive several pretty unpredictable results. single of our readers spent days tiresome to unearth what did you say? was mistaken with his code merely to realise the XINST morsel was unyielding.

LVP gives you the gift to curriculum the PIC using ICSP lacking requiring the "elevated" Vpp voltage. in attendance is a catch however - you need to dedicate the RB5 pin (PGM) to being an indicator if you are within indoctrination mode or else not. particular the PicKit2 generates the genuine voltage anyway, here doesnt seem to be real a plight of profit in switching this on instead of prototyping purposes.

to end with, the STVREN gives the option of having the PIC reset if the stack overflowed or else underflowed. If, for paradigm, you call too many nested functions, it would allow the PIC to reset. one time reset, you can examine why the PIC reset and present yourself a fault. We counsel leaving this on - if your PIC boots participating in the hub of responsibility something, you can sensibly simulate with the purpose of youve used up the stack pause (likely at what time youa propos deep in a nested location and in that case an interrupt occurs).

#pragma DATA _CONFIG4L, _STVREN_ON_4L & _LVP_sour_4L & _DEBUG_OFF_4L & _XINST_sour_4L

CONFIG5L gives the option of specifying if whichever solitary of four neighboring blocks of recollection are protected from any attempts by the PIC to alter (to be exact note down) the burst reminiscence ideals.

#pragma DATA _CONFIG5L, _CP0_sour_5L & _CP1_OFF_5L & _CP2_OFF_5L & _CP3_inedible_5L

CONFIG5H givest the option of caring the jam of reminiscence preliminary on 0x0000 to 0x7fff) - used by approximately bootloaders, like well as a spot to allow the protection of EEPROM recollection. The PicPack bootloader, "Boostbloader", resides appearing in higher recollection, import with the aim of while it is to some extent a smaller amount robust than a safe-down, physically protected bootloader, it doesnt require the "twin vault" in support of interrupts to bootloaders located in drop recollection accomplish. We may possibly provide this being an option in the hope.

#pragma DATA _CONFIG5H, _CPB_rancid_5H & _CPD_OFF_5H

CONFIG6L allows the protection of recollection blocks being send a letter to protected.

#pragma DATA _CONFIG6L, _WRT0_rancid_6L & _WRT1_OFF_6L & _WRT2_sour_6L & _WRT3_OFF_6L

CONFIG6H, CONFIG7L and CONFIG7H assign further granular protection, allowing blocks of reminiscence to be situated protected from whilst the code being executed is not concerning the same oppose. We might, in favor of exemplar, build a bootloader so as to was "secret" and unable to be timely by several other code.

#pragma DATA _CONFIG6H, _WRTC_rotten_6H & _WRTB_OFF_6H & _WRTD_sour_6H

#pragma DATA _CONFIG7L, _EBTR0_inedible_7L & _EBTR1_OFF_7L & _EBTR2_sour_7L & _EBTR3_OFF_7L

#pragma DATA _CONFIG7H, _EBTRB_rancid_7H

While narrowly speaking theyregarding not config language, the DEVID words allow code to determine which prototypical of the damage is running and which hardware revision. This is vital once at hand are bugs fashionable the hardware with the purpose of are fixed in excess of poles apart revision levels and code needs to kill differently based on the outcome.

Making configs

Youve probably worked old hat by at this moment with the purpose of the Sourceboost compilers config defines are expertly conceived so that you can simply & laid back the appropriate options; this wealth you dont need to be successful out exactly which spot positions act pardon?. The #pragma DATA gives you the skill to shove a byte happening a individual location (in our circumstances, into a config word slot).

Other PICs

at this junctures the config we depletion with the PIC16F88:

#pragma DATA _CONFIG, _CP_sour & _CCP1_RB0 & _DEBUG_OFF & _WRT_safeguard_inedible & _CPD_OFF & _LVP_OFF & _PWRTE_sour & _WDT_OFF & _PWRTE_ON & _BODEN_rotten &_MCLR_ON & _INTRC_IO

Yep, with the intention ofs privilege, its solely individual word sustained. nearly of these options willpower probably be present familiar to you already.

Troubleshooting

If your damage is not behaving and you fancy to effect impossible if youve made a faux pas hip your config bits, and dexterous hint is to use Microsofts MPLAB IDE to import the.magic charm box file youve produced by clicking on Menu | Import... next Configure | Configuration Bits... at this points the screen youll discover while importing the PIC18F2620 BoostBloader.

You can even variation the config bits if you would like, it follows that export again in the function of a.magic charm file, although keep happening mind this doesnt change your source code itself.

what did you say? youve probably realised at this point is with the purpose of the bootloader categorically has config bits embedded in the.curse line. Our usual PicPack programs dont - since we simulate youwith regard to running with a bootloader already installed. If you work out neediness to predetermine candidly with ICSP, of stream youll need to benefit config bits to be selected for your PIC run the way you be determined. Check banned the configbits.h file used by Boostbloader - weconcerning early to build up a files of near config bits as well as particular configuration options to veer for all things on or else rotten (these you effortlessly place taking part in the config.h dossier in your project).

This simple circuit aims to provide an indication of an appliance if it is ON or OFF with the use of green and red LEDs.

• BC337 – a small signal NPN Silicon AF medium power transistor used for general purpose switching and amplifying applications with features such as TO-18 manufactured package, suited for AF driver stages and low power output stages, and divided into three group types.
• Single Pole Single Throw (SPST) – a single on-off switch where the two terminals are either connected together of not connected to anything

The indication produced by the LEDs could mean that the red LED will illustrate that the equipment is turned ON while the green LED will illuminate upon turning OFF the same appliance. It could also be the other way around since green normally signifies that there is life on an equipment. This is applicable with any appliance that is powered and operated by AC mains which can be 230 V or 115 Vac.

A suitable switch SW1 made of single pole single throw type will be capable of handling the full load current. These switches can be in the form of toggle switch, push-to-make switch, push-push switch, tilt switch, reed switch, DIP switch, or push-to-break switch. During the operation, the load and the red diode D4 are being energized when the contacts of switch SW1 is closed. At this stage, the transistor Q1 will get saturated and shorts the green diode D3 which prevents it from illuminating.

Equipment Indicator Using Two LED Schematic



The explanation of the circuit operation pertains to a 230 Vac source. If the source would be coming from 115 Vac mains, the value of R1 and R2 should b3 15K Ohms at 1 W power output. The use of the type of switch SW1 should be able to withstand the full load voltage and current of the equipment.The two LED indicator can are widely used in several equipments and gadgets like the mobile phones. A blackberry phone have a LED indicator that can provide four colors depending on the status of the phone if it is receiving a message or a call, if connected via Wi-Fi, or if connected via Bluetooth. The good thing about the circuit is that it can be used for emergency light indicator, signal light, backup light, dashboard light, or with flash buzzer based on the AD signal light.

Using the LTC4078 standalone linear charger circuit you can design a very simple single-cell battery charger circuit for Li-Ion Li-Polymer battery . This LTC4078 battery charger circuit works from both wall adapter and USB inputs. This charger can detect power at the inputs and automatically select the appropriate power source for charging.

Battery Charger Using LTC4078 Circuit diagram


As you can see in the circuit diagram , this Li-Ion Li-Polymer charger requires few external components and you will need to apply just few equations ,to design a full work USB , wall adapter charger .
The charge current can be programmed up to 950mA from wall adapter input . IUSB pin is used for program the charge current for USB power that can be programmed by connecting a resistor to the ground.

The voltage on this pin can be used to measure the battery current delivered from the USB input using the following formula: IBAT = (VIUSB/RIUSB)*1000 . ITERM pin is the termination current threshold program that is set by connecting a resistor to ground. ITERMINATE is set by the following formula:
ITERMINATE =100V/RITERM ; RITERM =100V/ITERMINATE IDC pin is used for program the charge current for wall adapter power that is set by connecting a resistor to ground.The voltage on this pin can be used to measure the battery current delivered from the DC input using the following formula: IBAT = (VIDC/RIDC)*1000 .

The charge current delivered to the battery from the wall adapter or USB supply is programmed using a single resistor from the IDC or IUSB pin to ground and can be calculated using the following equations:
RIDC =1000V/ICHRG-DC , ICHRG-DC = 1000V/RIDC - Wall adapter
RIUSB =1000V/ICHRG-USB , ICHRG-USB =1000V/RIUSB – USB port.

The TCA62735AFLG is a charge pump type DC DC Converter specially designed for constant current driving of white LED.IC can outputs LED current 120mA or more to 2.8-4.2V input.IC observes the power-supply voltage and the output voltage, and does an automatic change to the best of step up mode 1, 1.5 or 2 times. It is possible to prolong the battery longevity to its maximum.This IC is especially for driving back light white LEDs in LCD of PDA, Cellular Phone, or Handy Terminal Equipment.

Schematic



This electronic project t LED driver is very simple and require few external electronic parts. Due of simplicity of this circuit this project not require additional explanations . If you want to change this design , please consult the manufactured datasheet .Some features of the TCA62735AFLG electronic project are Switching Frequency : 1MHz(Typ.), Output Drive Current Capability : Greater than 120mA , 4 Channels Built in Constant Sink Current Drivers, Sink Current Adjustment by External Resistance, Soft Start Function , Integrated protection circuit TSD (Thermal Shut Down) .

Using TEA5551T monolithic integrated radio circuit can be designed a AM radio receiver circuit which is designed for use as a portable radio receiver with headphones . 

AM Radio Receiver Circuit diagram

The TEA5551T radio receiver circuit contains all is needed for a AM radio receiver circuit (a complete AM part and dual AF amplifier with low quiescent current).The TEA5551T support a input voltage range (VS) from 1.8 V to 4.5 V but the typical voltage is 3 volts .Because in most case we don’t find to buy inductors you need to build the inductors L1 , L2 , L3 . In the picture bellow you can see the construction data for these three inductors .

The video amplifier in the diagram is a well-known design. Simple, yet very useful, were it not for the ease with which the transistors can be damaged if the potentiometers (black level and signal amplitude) are in their extreme position. Fortunately, this can be obviated by the addition of two resistors. If in the diagram R3 and R4 were direct connections, as in the original design, and P1 were fully clockwise and P2 fully anticlockwise, such a large base current would flow through T1 that this transistor would give up the ghost.

Moreover, with the wiper of P2 at earth level, the base current of T2 would be dangerously high. Resistors R3 and R4 are sufficient protection against such mishaps, since they limit the base currents to a level of not more than 5 mA. Shunt capacitor C4 prevents R4 having an adverse effect on the amplification.

Author: L.A.M. Prins

Copyright: Elektor Electronics

Source: http://www.extremecircuits.net/2010/07/video-amplifier.html

The LM3886 is a high-performance audio power amplifier capable of delivering 68W of continuous average power to a 4 load and 38W into 8 with 0.1% THD+N from 20Hz-20kHz.

features:

Maximum Output Power : 68W RMS - 108W Peak

THD : %0.03 at 60W

SNR : 110dB at 60 W - 92.5dB at 1W

PSRR : 120dB

Protection circuitries : DC /AC Short circuit protection and thermal protection

Output Class : Conjugate AB-A

Here is a circuit 120 watt stereo amplifier using STK4241V. The MAX9710 a stereo audio power amplifier capable of delivering 2 x 120 W of the IC to put loads of 8 ohms. MAX9710 can be operated from ± 32V single power supply of ± 54V.

This amplifier circuit is ideal for audio devices for home supply. STK4241V amplifier specifications might lead one to believe that you can use supply voltages of ± 78V. With zero input signal (and therefore no way out) I could, but I would not recommend anything better than ± 45V 8-ohm loads, if expected, although ± 54V will be fine if you can provide a good heat sink.