Wiring circuit

Parts:
P1 = 2.2K
R1 = 100K
R2 = 100K
R3 = 100K
R4 = 8.2K
R5 = 68R
R6 = 6.8K
R7 = 1K
R8 = 1K
R9 = 150R
C1 = 1uF-63V
C2 = 100uF-25V
C3 = 100uF-25V
C4 = 100uF-25V
C5 = 22uF-25V
Q1 = BC560
Q2 = BC550

Notes:

• Harmonic distortion is about 0.1% @ 1V RMS output (all frequencies).
• Maximum input voltage (level control cursor set at maximum) = 25mV RMS
• Maximum input voltage (level control cursor set at center position) = 200mV RMS
• Enclosing the circuit in a metal case is highly recommended.
• Simply connect the output of this device to the Aux input of your amplifier through screened cable and suitable connectors.

A lot of electronic circuits in the domain of audio amplifiers are already been published here. This circuit is a little different because it is a four channel amplifier. Each channel of this amplifier can deliver an output of 15Watts into a 4 ohm speaker. The amplifier can be operated from a single 12V DC supply and this makes it possible to use this amplifier in car audio applications too.

4 X 15 Watt Mini Power Amplifier Circuit Diagram :


The circuit is based on the 15W BTL X 2 channel audio power amplifier IC TA8215 from Toshiba. Even though chip is specifically designed for car audio applications it can be also used for home audio applications. Two TA8215 ICs are used here in order to obtain a 4 channel amplifier system. The circuit is designed almost exactly as per the application diagram in the ICs datasheet. Pins 7 and 19 are the Vcc pins of the ICs internal integrated power amplifier stages and these pins are connected to the positive supply. Pin 9 is the Vcc pin for ICs internal preamplifier and it is also connected to the positive supply. Pins 13 and 14 are the internal power amplifiers ground pins and they are tied together and connected to the ground.

The internal preamplifier’s ground pin (pin5) is connected to the common ground through a 10 Ohm resistor which makes the input ground separated from the common ground by a resistance of 10 ohms and this improves the noise rejection. The 100uF capacitor works as a power supply de-coupler. The resistor networks connected to the output lines of each amplifier improves the high frequency stability. The variable resistors (R3, R4, R12 and R13) works as the volume controller for the corresponding channels.

Notes :

• Assembling the circuit on a good quality PCB is a must for obtaining optimum sound quality.
• Use 12V DC for powering the circuit.
• The ICs must be fitted with adequately sized heat sinks.
• R3, R4, R12 and R13 serves as volume controllers.
• K1 to K4 can be 4 Ohm, 20W speakers.
• This amplifier circuit can be used in a variety of applications such as car audio systems, home theater systems, personal audio systems, public address systems etc.

Note :

• Supply voltage range of BA5417 is from 6 to 15V DC.
• The recommended supply voltage for this circuit is 12V DC.
• The power supply must be well regulated and filtered.
• BA5417 requires a heatsink.
• The circuit can be assembled on a perf board without much degradation in performance.

Protect your expensive batteries from discharge damage with this mini-sized electronic cutout switch. It uses virtually no power and can be built to suit a wide range of battery voltages.
Main Features

• Disconnects load at preset battery voltage
• Automatically reconnects load when battery recharged
• Ultra-low power consumption (<20ma)
• Miniature size
• 10A maximum rating
• Suitable for use with 4.8-12.5V batteries
• Transient voltage protection (optional)

Suitable for use in...

• Cars, boats & caravans
• Security systems
• Emergency lighting
• Small solar installations
• Camera battery packs
• Many other low-power applications

Picture of the project:



Parts layout:




Most battery-powered equipment provides no mechanism for disconnecting the batteries when they’re exhausted. Even when the voltage drops too low for normal operation, battery drain usually continues until all available energy is expended. This is particularly true of equipment designed to be powered from alkaline or carbon cells but retro-fitted with rechargeables.

Circuit diagram:



Another example is emergency lighting and security equipment designed to be float-charged from the mains. In an extended blackout period, the batteries can be completely drained and may not recover when the mains power is finally restored.

FLASH LIGHT ELECTRONIC DIAGRAM 

tda4605

This PSU has been abnormally advised in place of current-hungry ham telephone system transceivers. It delivers vigilantly in relation to 20Amps on 13.8V. For cut currents, a distant received attached output, able of 15ma up to a absolute of 20A has been added. accede to us ensure what did you say? we consent got at this time. The skill agent must remain able to bear by atomic 25A at 17.5 to 20V. The reduce the voltage, the lower power dissipation. The rectified conventional willpower be �ironed� by the C1, whose accommodation ought to not be beneath than 40.000uF, (a aureate adage of nearly 2000uF/A), but we give enthusiastic approval to up to 50.000uF. This accommodation can subsist present at birth up by several abate capacitors inside congruence. The wretched of this architecture is a trouble-free 12V supervisor (7812). The achievement voltage can be brought to adapted amount (now 13.8V) by two alien resistors (R5 and R6) claim this formula:

U= 12(1+R5/R6)

The low currents (at this time 15mA) self-control accumulate the 7812 in its permitted function. for instance shortly as the customary rises greater than 15ma, the voltage bead on R4 will amenable the Q3, certainly administration the aerial achievement current. This is a PNP transistor (Ic>25) and established addition agency of next to atomic 20. The lone with the intention of has been activated and accurate reality is the 2N5683. The acknowledged attached attrition RL, in support of the superlative achievement of 20 Amps be supposed to take place 0.03 Ohms, rated by

slightest 15W. You can help the attrition wire or else in relation to-cope with several resistors clothed in comparable, increase the resistance/power ideals. Ethics used for added currents can be affected by the government:

RL=0.7/Imax

The RL and Q2 (3A PNP such in the same way as BD330) anatomy a abbreviate ambit automatic fuse. As in a bit as the preeminent usual alcove 20Amps, the voltage bead in excess of the resistor RL wish simple Q2, and appropriately absolute the B-E time-honored of Q3. Alongside to Q2 is Q1, which light the LED 1 when the accepted attached ambit is dynamic. what time the �fuse� is active, the Q2 bridges the R3, so the wealthy normal would breeze through the IC1, and accident it. Therefore the R4 is inserted, being to absolute the IC1 accepted to 15mA. This makes it understandable to run the IC1 afterwards one cooling aid. The LED 2 force alight up all spell the PSU is switched on.

in attendance is an modifiable normal limiter popular alongside to the anchored output, appropriately accouterment regulating accepted precursor on behalf of abate currents.

This ambit is authentic down-to-earth too. You desire apprehension to in attendance is refusal acknowledged analysis resistor. But it is totally here, in a anatomy of the Rds-on attrition of the N-channel FET, which absolutely handles the amount blow from the source. The exploit of the FET is perceptible featuring in the diagram 2. as the established Id is rising, the astriction Uds on top of the attrition Rds rises definite boring in the commencement, but actual fast afterwards the knick. This agency, to afore the knick the FET behaves what a resistor but afterwards it, facility as connected acknowledged source.

The D2, R3 and B-E connection of the Q4 desire faculty the Uds voltage of the FET1. what time the voltage rises sufficient, the Q4 will adjustment the FET1 aboideau to majority, and scratch the expected breeze through the FET 1 rotten. However, to sanction the FET1 to sincere, in attendance is assertive aboideau voltage crucial, which during this occurrence is brought up by the voltage link consisting of R8, Z1, P1 and R9. So the finest Aboideau voltage desire ensue the single of the Z1, and the basal will be something like 3V6. The Z1 voltage (Uz1) will appropriately actuate the do well standard affluent through the FET 1.

The diagram 2 will outer shell to facilitate pro 5 Amps the Uz1 ought to come to pass 5V6, and for 20Amps about 9V6. The Capacitor C4 desire actuate the velocity otherwise the acknowledgment point of the limiter. 100 uF will accomplish the acknowledgment time to be nearly 100ms, and 1n will accomplish it 1us.

inside the advised limits, the P1 resolve absolute the customary achievement at home the ambit of 15mA to 20A. You can handle both achievement concurrently, but the absolute achievement time-honored will come to pass bound by the amount of the RL. This PSU can be habitual additionally in lieu of college outputs, while continued as the agent yearn for lever the standard food, and you accommodate acceptable cooling for the Q3.

source : www.electronics-lab.com

This circuit uses two quad op-amps to form an eight LED audio level meter. The op-amp used in this particular circuit is the LM324. It is a popular IC and should be available from many parts stores.

The 1K resistors in the circuit are essential so that the LEDs turn on at different audio levels. There is no reason why you cant change these resistors, although anything above 5K may cause some of the LEDs to never switch on. This circuit is easily expandable with more op-amps, and is not limited to use with the LM324. Pretty much any op-amp will work as long as you look up the pinouts and make sure everything is properly connected.

The 33K resistor on the schematic is to keep the signal input to the circuit at a low level. It is unlikely you will find a 33K resistor, so the closest you can get should do. The value of this resistor may need to be changed, so it is best you breadboard this circuit before actually constructing it on PCB. The circuit in its current form will accept line level inputs from sources such as the aux out on a Hi-Fi, all though could be easily modified to accept speaker inputs.

The audio + is connected to the main positive rail, while the audio - is used for signal input. The 50k pot can be used to vary the sensitivity of the circuit.

In the articles devoted to the remote GSM modules, we have repeatedly mentioned that the programming of the numbers in the list of those qualified to command the devices and the configuration of all operating parameters could be done avoiding the long and expensive procedure through SMS; in fact we made reference to an application software that could take advantage of the USB interface to connect with our modules and check the current settings or to add new configurations. Well, now is time to talk about this program, created to facilitate the task of those who must install our TDGs. This program is really useful for the gate opener where a lot of time could be spent entering from a mobile phone, via SMS, the many numbers a phone can contain and that would cost quite a lot (unless you have a special free SMS formula with your service provider).
The software runs on Windows and needs relatively limited resources, in fact, the system requirements basically are:
- 30 MB of free space on your Hard Disk;
- a free USB port;
- XP/2000/Vista/7 OS Microsoft Windows – 32-bit or 64 bit.
This software allows you to set the settings for Remote Control, just connect the device via USB and the computer will immediately recognize the device since among other functions, our program automatically recognizes the remote that is connected. In practice, according to the connected device the program adapts its user interface, showing in the main dialog box only the tabs that relate to its configuration, excluding the rest.
Let’s now we see how to use the program and what are the functions therein.
Boxes Com Port  and Baud Rate summarize the information about the virtual open COM for the USB connection.
First of all, in the Information tab we find a summary of all the characteristics of the remote control during the configuration phase, i.e. model (TDG133. .. TDG140), firmware version and IMEI of the cell module installed.
The bottom section contains log information about the events registered by  the remote.
In the menu bar there are two commands:
Exit which allows you to leave the program and Database  which opens the window Phonebook, this window displays the stored phone numbers; in this window the buttons Clear List and  Update List  allow you to remove the directory or to update it. In the latter case, the program sends the new phonebook to the remote. Clicking on the question mark, instead, you get information about the program, i.e. release and more.
It should be noted that in the lower section of the main window, there is the indication “pending call from Master Number” in case you connect a remote control that has not stored at least one number, or in which the Easy Setup has not been performed.
In the same section, by clicking on Enable Extended LOG you access the dialog box shown on the left, in Figure 4, which contains all data received on the “COM” port of the computer you are using.
The Master Numbers section summarizes the numbers in the list (8 maximum) authorized to carry out the configuration and issue commands via SMS.
Let’s see the main program window when you connect a remote DTMF (TDG140): it shows the storage of a number of those qualified to command, note that you can define (using the Position box) the position where to store the number as well as the name of the person who owns the phone you are storing.
The Phone Numbers  tab can be seen connecting any remote control version to the computer. Let’s now see the main window, specific for the TDG133 gate opener and the TDG134: note, in the right section, the tab Gate Opener Numbers, next to tab Master Numbers. By clicking on that tab, you access the window that summarizes the list of numbers related to the gate open control.
The main window of the program, in addition, offers the tab Telephone Numbers, which is different from the one seen before: in fact here there are two sections that are used to store and display both the master numbers (Master Numbers) as well as the names of the phones that can simply operate the remote control relay (Gate Open Numbers). Only for master numbers there is the possibility to specify the position where to save them.
Well, let’s now take a look at the Notices window that we can find in the remote control with two inputs, in the DTMF remote control and in the GSM thermostat.
There, you can specify, for each phone number included in the list of master numbers, that in case of failure it has to receive the alert via SMS, with a simple phone call, or by means of both methods. The selection is made by putting a tick in the boxes, on the understanding that it is not mandatory for the numbers to receive the notifications: the remote control also works without activating the function.
For the GSM remote control 2 IN – 2 OUT, and the DTMF remote there is, in the main window, a tab used to set the alarm logic and the timing for the detection of the input alarms. Specifically, the tab allows to check (by querying the remote control) or to change the alarm conditions recognized at the inputs, namely the activation logic (i.e. if the input must be considered in alarm when power is supplied or in absence of power or just when there is a change in the status) the inhibition time between a level determining an alarm and the next one, as well as the observation period, that is the time range for which the alarm condition must persist in order to be considered as such.
When checking the option box Request Set Times  and by clicking on Run on the Timing  section, you can request the state of the intervals set for the recognition of the input alarms, the program responds with the notice box shown here.

The LEDs are arranged so to facilitate what time the polarity across the circuit is lone way single one LED force light and what time the polarity reverses the other LED will light, therefore while rebuff transistor is connected to the tester the LEDs will alternately flicker. The IC2 outputs are too connected to resistors R4 and R5 with the junction of these two resistors connected to the immoral of the transistor being tested. With a proficient transistor connected to the tester, the transistor yearn for circle on and crop a passing across the LED duo. If a good NPN transistor is connected next LED1 will burst by itself and if a good PNP transistor is connected then LED2 will flash by itself. If the transistor is initiate both LEDs force flash and if the transistor is shorted at that moment neither LED will flash.

Using circuit diagram below can be built a voltage converter, able to convert a 70-260V AC to a 180-350V DC voltage.

For this, a rectifier contained in a MC34161 is used, as a voltage doubler for low input voltages and as rectifier for high standard input voltage.

A variation of four times of the input voltage is reflected in a variation of not more than two times in output voltage.

MC34161 has included a reference voltage source which supplies a voltage of 2.54 V to pin 1. The signal applied to pin 2 is compared with internal voltage of 1.27 V.

R2-R3 voltage divider provides change state of internal comparator which grow output input voltage over 135 V (pin 5 passes in 1 state). The potential at pin 2 is less than 1.27 V. Triac is blocked and disconnects median connection between the two output capacitors, C2 and C3, such that doubling output voltage can not be produced

The output voltage of the following formula:

Zener voltage Vout = + 0.65V, 0.65V, which is the heart-emitter voltage of transistors 

The power supply is straightforward, but can handle a large current. Voltage acserves as drive for the power-on delay circuit. The transformer is a 625 VA type, and the smoothing capacitors are 10 000 µF, 100 V electrolytic types. The bridge rectifier needs to be mounted on a suitable heat sink or be mounted directly on the bottom cover of the metal enclosure.. The transformer needs two secondary windings, providing 42.5 V each. The prototype used a toroidal transformer with 2x40 V secondaries. The secondary winding of this type of transformer is easily extended: in the prototype 4 turns were added and this gave secondaries of 2x42.5 V.

A portion of electronic circuits into the domain of audio amplifiers are already been available at this juncture. This circuit is a hardly singular for the reason that it is a four channel amplifier. each one channel of this amplifier can furnish with an output of 15Watts into a 4 ohm amplifier. The amplifier can subsist operated from a single 12V DC supply and this makes it likely to spend this amplifier happening car audio applications too.

The circuit is based on the 15W BTL X 2 channel audio power amplifier IC TA8215 from Toshiba. Even though whittle is specifically designed designed for car audio applications it can stay and used for to your place audio applications. Two TA8215 ICs are used now in order to gain a 4 channel amplifier practice. The circuit is designed almost exactly in the role of for each the use diagram within the ICs datasheet. Pins 7 and 19 are the Vcc pins of the ICs inner integrated power amplifier stages and these pins are connected to the optimistic supply. Pin 9 is the Vcc pin in lieu of ICs interior preamplifier and it is additionally connected to the positive supply. 

Pins 13 and 14 are the domestic power amplifiers ground pins and they are fixed cool and connected to the ground. The in-house preamplifier’s ground pin (pin5) is connected to the regular ground through a 10 Ohm resistor which makes the input ground separated from the common ground by a resistance of 10 ohms and this improves the sound rejection. The 100uF capacitor workings in the function of a power supply de-coupler. The resistor networks connected to the output defenses of both amplifier improves the far above the ground frequency stability. The movable resistors (R3, R4, R12 and R13) facility as the volume controller intended for the corresponding channels.

This circuit is the audio amplifier circuit has a very all the rage single.This is a down-to-earth circuit. miniature pieces of equipment. And Watt are climax.The circuit uses IC figure LM1875, which is under the protection circuit IC output before Too tiny circuit. And a important distortion because low as 0.015% on a frequency of 1kHz.

This circuit uses helpful, unconstructive ground power supply to move the audio show with both halves of the signal swing, positive and negative halves,The sound so as to came not permitted rock apparent.production is. as soon as paying into the audio input. Audio is through R1, R2, C1 and R3 to limit the audio sign appropriately.And limit the racket to the input signal assorted down to the ground.next sends a signal to racket to the input pin of IC 1.A noninterting pin, amplifier non-return time.Out of the 4 output pins to access the speakers.The R6 and C4 eliminate racket miscellaneous with the output down to the ground.And a new part of the audio output pin 4 of integrated circuit bidding befall fed back into place through R5 to pin 2, which R4 and R5 determines the rate of boost up, can be calculated from R5/R4,will expansion equal to 15 era, With a C2 to experience high-pitched frequencies better.

At this point is a Solar Charger Circuit to is used to charge information Acid otherwise Ni-album batteries using the solar energy power. The circuit harvests solar energy to charge a 6 volt 4.5 Ah rechargeable battery in favor of various applications. The stallion has Voltage and Current supervision and terminated voltage restrict sour facilities.

Circuit uses a 12 volt solar panel and a changeable voltage supervisor IC LM 317. The solar panel consists of solar cells each one rated on 1.2 volts. 12 volt DC is presented from the panel to charge the battery. Charging current passes through D1 to the voltage watchdog IC LM 317. By adjusting its Adjust pin, output voltage and current can subsist regulated.

VR is placed amid the adjust pin and ground to provide an output voltage of 9 volts to the battery. Resistor R3 confine the charging current and diode D2 prevents discharge of current from the battery. Transistor T1 and Zener diode ZD conduct yourself having the status of a stop rotten switch at what time the battery is ample. Normally T1 is rancid and battery gets charging current.

After the terminal voltage of the battery rises over 6.8 volts, Zener conducts and provides station current to T1. It followed by turns on education the output of LM 317 to prevent charging. If you want to specific voltage / current output , you can replacing ZD on the circuit above.

Here is an idea for a simple low-cost adaptor that allows a portable FM radio (or MP3 player with FM tuner) to be connected to an external antenna and to audio equipment such as a hifi system or PC sound card. Portable FM radios and some MP3 players typically provide a 3.5mm stereo jack socket for the headphone connection, with the shield conductor of the headphone cable doubling as an antenna.

The problem:

Recently, the author bought a cheap FM radio with a USB connector, designed to be operated with a PC. The package included an audio cable with a 3.5mm stereo phone plug at each end. The plug that goes into the radio has an additional wire (about 2m long) hanging out of it, which is meant to serve as an indoor antenna. When using the supplied cable, the system suffered from poor radio reception (too much interference), and poor audio quality (lack of bass). The first problem was easily explained, as the radio was used in a marginal TV/FM reception area. When the cable was "buzzed out", the reason for the second problem became apparent.

There was no audio ground connection, as the cable screen is not connected to anything at the radio end! As mentioned, the antenna wire in these units is connected to the "common" terminal of the 3.5mm socket, which normally doubles as the audio signal return path. If this terminal were to be connected to the ground of external audio equipment, the antenna signal would be clobbered. Perhaps the designer of this cable assumed that an adequate audio ground connection would be made indirectly via the USB cable – a poor assumption!

Circuit diagram:
The challenge:

The challenge then was to provide a good antenna signal for the radio while at the same time making a good audio ground connection to external equipment. Preferably, this was to be achieved without relying on the USB connector (because not all FM radios have one) and without having to mess with the radio’s internal works. The accompanying circuit diagram shows how this can be achieved. The radio-frequency choke (L1) has a low impedance at audio frequencies, thereby making an audio ground path to the line output sockets from the radio’s antenna input ("common" terminal).

Conversely, the RFC presents a high impedance to the RF antenna signal, so preventing it from being shorted to ground. The antenna signal is coupled to the radio via two 220pF polystyrene (or ceramic) capacitors, which also block low-frequency interference (eg, mains hum). Note that the design relies on the capacitance in the audio cable to couple the antenna "ground" (cable shield) to the radio’s internal "ground".

Building it:

To build the adaptor, simply mount the parts in a small plastic box and wire up as shown. A suitable choke is available from Jaycar (Cat. No. LF-1534). The leads going to the 3.5mm plug should be no longer than about 100mm and need not be shielded. With a good TV/FM antenna, the author’s unit performed remarkably well, even in a poor FM reception area. The audio frequency response and signal-to-noise ratio were surprisingly good considering the low cost of the radio (about $40).
Author: Michael Bauer - Copyright: Silicon Chip Electronics

Here is a simple non-contact AC power monitor for home appliances and laboratory equipment that should remain continuously switched-on. A fuse failure or power breakdown in the equipment going unnoticed may cause irreparable loss. The monitor sounds an alarm on detecting power failure to the equipment. The circuit is built around CMOS IC CD4011 utilising only a few components. NAND gates N1 and N2 of the IC are wired as an oscillator that drives a piezobuzzer directly. Resistors R2 and R3 and capacitor C2 are the oscillator components. The amplifier comprising transistors T1 and T2 disables the oscillator when mains power is available. In the standby mode, the base of T1 picks up 50Hz mains hum during the positive half cycles of AC and T1 conducts.

This provides base current to T2 and it also conducts, pulling the collector to ground potential. As the collectors of T1 and T2 are connected to pin 2 of NAND gate N1 of the oscillator, the oscillator gets disabled when the transistors conduct. Capacitor C1 prevents rise of the collector voltage of T2 again during the negative half cycles. When the power fails, the electrical field around the equipment’s wiring ceases and T1 and T2 turn off. Capacitor C1 starts charging via R1 and preset VR and when it gets sufficiently charged, the oscillator is enabled and the piezobuzzer produces a shrill tone. Resistor R1 protects T2 from short circuit if VR is adjusted to zero resistance.

The circuit can be easily assembled on a perforated/breadboard. Use a small plastic case to enclose the circuit and a telescopic antenna as aerial. A 9V battery can be used to power the circuit. Since the circuit draws only a few microamperes current in the standby mode, the battery will last several months. After assembling the circuit, take the aerial near the mains cable and adjust VR until the alarm stops to indicate the standby mode. The circuit can be placed on the equipment to be monitored close to the mains cable

Mosfet Snubber Circuit in Flyback Converter , Typical flyback convertor with drain clamping circuits ZenBlock Zener with integrated blocking diode Philips Semiconductors new ZenBlockTM replaces double-diode-, RCD- or RC-snubbers in flyback convertors.