Showing posts with label using. Show all posts

Friday, October 3, 2014

FM Radio Using TDA7000

Here’s a design simple circuit using TDA7000 that can build an FM radio with a minimum of components; most of them so easy to manage, like the ceramic capacitors that do not require polarization and only two resistors. Here’s the figure of the circuit;

The components you will employ will be of small dimensions and low cost. Even the integrated circuit itself, the TDA 7000, is not of great cost.

Friday, September 19, 2014

Simple and hold circuit using op amp Circuits Wiring diagram

As the name indicates , a sample and hold schema is a schema which samples an input signal and holds onto its last sampled value until the input is sampled again. Sample and hold diagram are commonly used in analogue to digital converts, communication diagram, PWM diagram etc. The schema shown below is of a sample and hold schema based on uA 741 opamp , n-channel E MOSFET BS170 and few passive components.

Description

As the name indicates , a sample and hold schema is a schema which samples an input signal and holds onto its last sampled value until the input is sampled again. Sample and hold diagram are commonly used in analogue to digital converts, communication diagram, PWM diagram etc. The schema shown below is of a sample and hold schema based on uA 741 opamp , n-channel E MOSFET BS170 and few passive components.

In the schema MOSFET BS170 (Q1) works as a switch while opamp uA741 is wired as a voltage follower. The signal to be sampled (Vin) is applied to the drain of MOSFET while the sample and hold control voltage (Vs) is applied to the source of the MOSFET. The source pin of the MOSFET is connected to the non inverting input of the opamp through the resistor R3. C1 which is a polyester capacitor serves as the charge storing device. Resistor R2 serves as the load resistor while preset R1 is used for adjusting the offset voltage.

During the positive half cycle of the Vs, the MOSFET is ON which acts like a closed switch and the capacitor C1 is charged by the Vin and the same voltage (Vin) appears at the output of the opamp. When Vs is zero MOSFET is switched off and the only discharge path for C1 is through the inverting input of the opamp. Since the input impedance of the opamp is too high the voltage Vin is retained and it appears at the output of the opamp.

The time periods of the Vs during which the voltage across the capacitor (Vc) is equal to Vin are called sample periods (Ts) and the time periods of Vs during which the voltage across the capacitor C1 (Vc) is held constant are called hold periods (Th). Taking a close look at the input and output wave forms of the schema will make it easier to understand the working of the schema.

Circuit diagram

Sample and Hold schema using uA741 opamp

Input and output waveforms.

Input and output waveforms - Sample and hold schema

Notes

The schema can be assembled on a vero board.
Use +15V/-15V DC dual supply for powering the opamp.
Capacitor C1 must have minimum leakage current possible and thats why a polyester capacitor is used here.
Mount the IC uA741 on a holder.
The type number of the MOSFET Q1 is not very significant here and so substitution is possible if BS170 is not available.
BS170 is a 60V, 500mA n-channel enhancement mode MOSFET available in TO-92 package.
Preset resistor R1 can be used for offset adjustments.

Wednesday, September 10, 2014

9 Volt DC Power Supply Using LM317 Regulator

There are many ways to obtain a very stable voltage 9VDC which has very minimal distortion. If you really love in the audio field, you must have a power supply at the level of the OP Amp should be free from hum. Use of Power Supply which has a higher stabilization and free of humming and buzzing frequently encountered in the use of communication tools such as Handy-talkie and radio transmitters.

To overcome the above problem, we have to provide the filters on the power supply using IC regulator. You can use the LM 7809 or you can also use the regulator IC LM 317. This regulator has advantages over the use of IC 78XX. LM317 has a nature that is at the Gate (no.1 feet) can be tuned to provide feedback which is inversely proportional to the value of R (resistor). The R value can affect the output voltage on pin 2(V-out), pin 3 as input (V-in). The function R can be replaced with a variable resistor, but you must have an indicator meter or AVO meter to ensure that the output voltage is true 9 Volt. If youve found your desired voltage, for example 9VDC, then you can connect to the component that you want to turn on. So first set the output voltage using a volt meter before connecting to the equipment to be you turn on.

KA317 / LM317 is a Three Terminal Positive Adjustable Regulator integrated schema, the monolithic characteristic adjustable positive voltage regulator designed to supply more than 1.5 A of load current with output voltage can be adjusted with a range capability 1.2 V of up to 37 V. This tool will work for internal current limiting, thermal shut-down and securing the compensation scope. You have to use aluminum as an additional cooling.

This schema will deliver 9V regulated DC voltage at maximum current of about 1A. The schema uses a transformer with a secondary output voltage 15-24V AC/1A. To give input in Primary of transformer, it’s dependent electrical conduit installation in your home. If the mains voltage 110V, then you have to find a 110V in transformer primary voltage. For the diode, you can use 4 pieces diodes 1N4002 (1A rectifier diode) or better by using a diode bridge 2A.

9 Volt DC Power Supply Using LM317 Regulator

In the following schema scheme, we can see the typical basic application into obtaining voltage can be adjusted.

Monday, September 8, 2014

Long range Burglar Alarm Using Laser Torch

Laser torch-based burglar alarms normally work in darkness only. But this long-range photoelectric alarm can work reliably in daytime also to warn you against intruders in your big compounds, etc. The alarm comprises laser transmitter and receiver units, which are to be mounted on the opposite pillars of the entry gate. Whenever anyone enters to interrupt the transmitted laser beam falling on the receiver, the buzzer in the receiver schema sounds an alarm.

The range of this burglar alarm is around 30 metres, which means you can place the transmitter and the receiver up to 30 metres apart. Since the laser torch can transmit light up to a distance of 500 metres, this range can be increased by orienting the phototransistor sensor properly. To avoid false triggering by sunlight, mount the phototransistor sensor such that it doesn’t directly face sunlight.

Long-range Burglar Alarm Using Laser Torch

Fig. 1: Circuit of laser torch based transmitter

The transmitter schema is powered by 3V DC. The astable multivibrator built around timer 7555 (IC1) produces 5.25kHz frequency. CMOS version of timer 7555 is used for low-voltage operation. The body of the laser torch is connected to the emitter of npn transistor T1 and the spring-loaded lead protruding from inside the torch is connected to the ground.

The receiver schema is powered by 12V DC. It uses photoDarlington 2N5777 (T2) to sense the laser beam transmitted from the laser torch. The output beam signals from photoDarlington are given to the two-stage amplifier followed by switching schema, etc. As long as the laser beam falls on photoDarlington T2, relay RL1 remains un-energised and the buzzer does not sound. Also, LED1 doesn’t glow.

Long-range Burglar Alarm Using Laser Torch

Fig. 2: Receiver schema

When anyone interrupts the laser beam falling on photoDarlington T2, npn transistor T6 stops conducting and npn transistor T7 is driven into conduction. As a result, LED1 glows and relay RL1 energises to sound the buzzer for a few seconds (determined by the values of resistor R15 and capacitor C10). At the same time, the large indication load (230V AC alarm for louder sounds or any other device for momentary indication) also gets activated as it is connected to 230V AC mains via normally opened (N/O) contact of relay RL1.

Sourced By : EFY Author: Pradeep G.

Wednesday, September 3, 2014

Fan Controller Using Just Two Component

The Maxim MAX 6665 (www.maxim-ic.com) provides a complete temperature-dependent fan controller. It can switch fans operating at voltages of up to 24 V and currents of up to 250 mA. The IC is available from the manufacturer in versions with preset threshold temperatures between +40 °C (MAX6665 ASA40) and +70 °C (MAX6665 ASA 70). The device’s hysteresis can be set by the user via the HYST input, which can be connected to +3.3 V, connected to ground, or left open. The following table shows the hysteresis values available:

HYST = Hysteresis
open = 1 °C
ground = 4 °C
+3.3V = 8 °C

Fan Controller Using Just Two Component Circuit diagram:

Fan Controller Circuit Diagram

The other pins of the SO8 package are the FORCEON input and the status outputs WARN, OT and FANON. The test input FORCEON allows the fan to be run even below the threshold temperature. The open-drain output WARN goes low when the temperature rises more than 15 °C above the threshold temperature, while the open-drain output OT indicates when the temperature is more than 30 °C above the threshold. The push-pull output FANON can be used to indicate to a connected microcontroller that the fan is turned on.

Source by : Streampowers

Monday, September 1, 2014

Eliminator 1 5 Volt battery using LM317

This schema is a battery eliminator 1.5 V, that is, a power supply of 1.5 volts, low consumption that takes as input the output of the USB PC or notebook. The power adapter is simple, it converts the voltage from 5V to 1.5V USB ports, using the popular LM317 IC and a few other components. To be exact this schema uses only three components, one is the LM317, R1 = R2 = 470 ohm and 100 ohm.

Eliminator 1.5 Volt battery using LM317 Circuit Diagram

Wednesday, August 27, 2014

MHz Oscillator using an ATtiny15 Wiring diagram Schematic

Most engineers will recognise the problem: Your schema needs a stable 1 or 2 MHz clock generator (in the author’s case it was for a Pong game using an old AY3-8500). A suitable crystal is not to hand so you cobble together an RC oscillator (there are plenty of diagram for such a design). Now it turns out that you don’t have exactly the right capacitor so a preset pot is add e d to allow some adjustment . Before you know it the clock schema is taking up more space on the board than you had hoped.

Providing the application does not demand a precise clock source a tiny 8-pin microcontroller may offer a better solution to the problem. It needs no additional external components and an old ATtiny15 can be found quite cheaply. Another advantage of the solution is that clock frequency adjustment does not involve changing external components and is not subject to component tolerances.

The microcontroller’s internal RC oscillator is already accurately calibrated to 1.6 MHz. With its inbuilt PLL, internal Timer 1 can achieve up to 25.6 MHz [2]. By configuring internal dividers the timer can output a frequency in range of roughly 50 kHz up to 12 MHz from an output pin. The difference between calculated and the actual output frequency increases at higher frequencies. A meaningful upper limit of about 2 MHz is a practical value and even at this frequency the deviation from the calculated value is about 15 %.

MHz Oscillator using an ATtiny15 Schematic

The schema diagram could hardly be simpler, aside from the power supply connections the output signal on pin 6 (PB1) is the only other connection necessary.The example program, written in Assembler is just 15 lines long! With a program this short comments are almost super fluous but are included for clarity. The code can be downloaded from the Elektor website [1].

The program only needs to initialise the timer which then runs independently of processor control to output the clock sign al . The processor can then be put into sleep mode to memory used up the remaining 99 % is free for use for other tasks if required.

The OSCCAL register contains a calibration byte which allows some adjustment of the CPU clock. This gives a certain degree of fine tuning of the output frequency. A recommendation in the Atmel data sheet indicates that the CPU clock frequency should not be greater than 1.75 MHz otherwise timer operation cannot be guaranteed.

The more recent ATtiny45 can be substituted for the ATtiny15. In this case the CK SEL fuses should be set to put the chip’s Timer 1 into ATtiny15- compatible mode [3]. After adjustment to the program it will now be possible to obtain a higher (or more exact) frequency from the timer, the ATtiny45’s PLL can operate up to 64 MHz.

Friday, August 22, 2014

60 Watt Amplifier using TDA2052

This is HiFi audio amplifier system. This amplifier is AB class amplifier and has very low distortion thats why this amplifier can be used for HiFi audio system. TDA2052 has mute and st-by functions so it can be controlled by external digital diagram. Very high temperature and output short schema protections are included. You should use a heatsink to dissipate the excess heat.

Functions of the Components:

R1 - Input Impedance
R2,R3 - Gain (32dB)
R4 - Input Impedance in Mute Mode
R5 - Standby Transition Time
R8 - Output Frequency Balancing
R9,R10 - Discharge Resistors
C1 - Input Coupling Capacitor
C3 - Feedback Coupling Capacitor
C4 - Standby Transition Time
C5 - Output Frequency Balancing
C6,C7 - Supply Stabilizing Capacitors
C9,C10 - Supply Filter Capacitors

Component List:

Component	Value	Number
R1,R2,R4,R5	11k ¼ W	4
R3	560, ¼ W	1
R6	7.5 K, ¼ W	1
R7	1 K, ¼ W	1
R8	4.7 , ¼ W	1
R9,R10	1.2 K, ¼ W	2
C1	2 uF/25 V	1
C3,C4	10 uF/25 V	2
C5,C9,C10	100 nF	3
C6,C7	1000 uF/40 V	1
U1	TDA2052	1

Monday, August 18, 2014

100 Watt Amplifier Circuit Using Transistors

Circuit Description

A amplifier incorporating an input filter stage, an intermediate driver stage and a powerful symmetrical output stage consisting of the versatile 2N3055 power transistors. The circuit efficiently drives a 100 watt 4 Ohms speaker with inputs derived from any audio source like a cell phone or DVD player etc.

100 watt amplifier circuit using 2N3055 transistors, a prior understanding of the involved circuit configuration would be very handy, let’s begin the explanation with the following points:

A quick glance at the given circuit diagram makes us conclude that the output configuration is not symmetrical, since the transistors T15 and T16 are both NPN types.

The input stage of the circuit begins or initiates with a symmetrical differential preamplifier stage consisting of the transistors T1, T2 and T3, T4. T5 and T6 are positioned as the current sources which are further extended as the driver stage consisting of the transistors T7 and T8. However a closer inspection tells us that of course the wiring is symmetrical, having the transistors T11, T13, T15 at the upper section acting like special booster transistor package. Similarly the lower section also employs identical super booster stage consisting of the transistors T12, T14 and T16. The above two sections are perfectly complementary to each other, with reference to the diagram which indicates their emitters being terminated to a common point through the resistors R25 to R27 and via R28 to R30, this effectively that the wiring is exclusively symmetrical by nature. The output stage is able to produce a massive 200,000 times amplification factor with comparatively very low quiescent current drain.

Though not absolutely necessary, for better thermal stability the transistors T9 and T11 and also T10 and T12 should be glued together, preferably by attaching the respective pairs face to face.

Circuit Diagram

100 Watt Amplifier Circuit Using Transistors

Parts List

R1 = 430 K,
R2 = 47K,
R3 = 330 Ohms,
R4, R5 = 12 K ,
R6, R7, R20, R21, R22, R23, R24 = 1 Ohm, 3 Watt, Wire Wound Type
R8, R17 = 68 Ohms,
R9 = 100 K,
R10, R11, R12, R13 = 5K6,
R14, R15 = 12 K,
R16, R19 = 100 Ohms,
R25 = 10 Ohms / 2 Watts,
P1 = 100 Ohms Preset, Linear
C1 = 1 µF / 25V,
C2 = 1 n, CERAMIC,
C3, C4 = 100Pf
C5 = 100 n,
C6, C7 = 1000 uF / 35 V,
L1 = 20 turns of enameled 1mm copper wire over R24,
D1, D2 = RED LED 5mm,
All other diodes are = 1N4148,
T1 = Matching BC546 pair,
T2 = Matching BC556 pair,
T3 = BC 557B,
T4, T7, T8 = BC 547B,
T5, T12 = BC 556B,
T6, T9 = BC 546B,
T10 = BD 140
T13 = BD 139
T11, T14 = 2N 3055
General Purpose PCB,
All the transistors T10, T13, T11 and T14 ae mounted on suitable heatsinks

Tuesday, August 12, 2014

Battery Discharger Using Discrete Components

The battery discharger published in this website may be improved by adding a Schottky diode (D3). This ensures that a NiCd cell is discharged not to 0.6–0.7 V, but to just under 1 V as recommended by the manufacturers. An additional effect is then that light-emitting diode D2 flashes when the battery connected to the terminals is ﬂat. The schema in the diagram is based on an astable multivibrator operating at a frequency of about 25 kHz. When transistor T2 conducts, a current flows through inductor L1, whereupon energy is stored in the resulting electromagnetic field. When T2 is cut off, the ﬁeld collapses, whereupon a counter-emf is produced at a level that exceeds the forward voltage (about 1.6 V) of D2.

A current then ﬂows through the diode so that this lights. Diode D1 prevents the current ﬂowing through R4 and C2. This process is halted only when the battery voltage no longer provides a sufficient base potential for the transistors. In the original schema, this happened at about 0.65 V. The addition of the forward bias of D3 (about 0.3 V), the ﬁnal discharge voltage of the battery is raised to 0.9–1.0 V. Additional resistors R5 and R6 ensure that sufficient current ﬂows through D3. When the battery is discharged to the recommended level, it must be removed from the discharger since, in contrast to the original schema, a small current continues to ﬂow through D3, R2-R3, and R5-R6 until the battery is totally discharged.

The flashing of D2 when the battery is nearing recommended discharge is caused by the increasing internal resistance of the battery lowering the terminal voltage to below the threshold level. If no current ﬂows, the internal resistance is of no consequence since the terminal voltage rises to the threshold voltage by taking some energy from the battery. When the discharge is complete to the recommended level, the LED goes out. It should therefore be noted that the battery is discharged sufficiently when the LED begins to ﬂash.

Streampowers

Using Serial Port PC Battery Charger Wiring diagram Schematic

This is one of the porters of the series "battery chargers that will never do." It uses the serial port of a PC to power a battery charger. A serial interface port can not supply enough current to charge batteries more powerful, but low capacity battery Nickel Cadmium (NiCd), this schema is more than enough.You could, for example, use the batteries in a radio and charge them while using the PC.

The three serial port connections TxD, DTR and RTS, when not in use, are -10 V and can provide a current of about 10 to 20 mA. The schema shown supplies a charging current of about 30 mA. If you need to change the polarity of the charging schema, then it is a simple job, just reverse the diodes and use of software, change door signs to 10 V. Those interested can also write a software routine that automatically recharges the batteries.

Serial Port PC Battery Charger Circuit Diagram