Panel switch wiring

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Monday, January 26, 2015

Low Cost Playback Amplifier For Cassette Deck

For some time now, there have been a number of tape cassette decks available at low prices from mail order businesses and electronics retailers. Such decks do not contain any electronics, of course. It is not easy to build a recording amplifier and the fairly complex magnetic biasing circuits, but a playback amplifier is not too difficult as the present one shows.

The stereo circuits in the diagram, in conjunction with a suitable deck, form a good-quality cassette player. The distortion and frequency range (up to 23 kHz) are up to good standards. Moreover, the circuit can be built on a small board for incorporation with the deck in a suitable enclosure. Both terminals of coupling capacitor C1 are at ground potential when the amplifier is switched on.

Cassette Deck Playback Amplifier Circuit Diagram:

Because of the symmetrical ±12 V supply lines, the capacitor will not be charged. If a single supply is used, the initial surge when the capacitor is being charged causes a loud click in the loudspeaker and, worse, magnetizes the tape. The playback head provides an audio signal at a level of 200–500 mV. The two amplifiers raise this to line level, not linearly, but in accordance with the RIAA equalization characteristic for tape recorders. Broadly speaking, this characteristic divides the frequency range into three bands:

Up to 50 Hz, corresponding to a time constant of 3.18 ms, the signal is highly and linearly amplified.
Between 50 Hz and 1.326 kHz, corresponding to a time constant of 120 µs, for normal tape, or 2.274 kHz, corresponding to a time constant of 70 µs, for chromium dioxide tape, the signal is amplified at a steadily decreasing rate.
Above 1.326 kHz or 2.274 kHz, as the case may be, the signal is slightly and linearly amplified. This characteristic is determined entirely by A1 (A1’). To make the amplifier suitable for use with chromium dioxide tape, add a double-pole switch (for stereo) to connect a 2.2 kΩ resistor in parallel with R3 (R3’). The output of A1 (A1’) is applied to a passive high-pass rumble filter, C3-R5 (C3’-R5’) with a very low cut-off frequency of 7 Hz. The components of this filter have exactly the same value as the input filter, C1-R1 (C1’-R1’). The second stage, A2 (A2’) amplifies the signal ´100, that is, to line level (1V r.m.s.).

Thursday, September 18, 2014

Batteries Charger PSU Ideal for Digital Cameras

This circuit was created for digital cameras. Its known the digital cameras have considerable power consumption. For example my camera Minolta E223 requires approximately 800 mA. In practice a mains power supply or high capacity NiMH accumulators (batteries) can satisfy this demand. Batteries Charger & PSU Circuit diagram: This circuit consists of two parts, charger and adapter. The transformer, rectifier bridge and buffer condensator are common. Adapter is quite simply its main part is an adjustable voltage regulator LM 317 according to usual setting. Output is a suitable for camera jack plug. Voltage can be adjusted in range 2-9 V. In the charger circuit a 7805 fixed voltage regulator works as current generator assured constant current during charging. This charging current can be adjusted with the 100 /1W potentiometer in range about 50-300 mA indicated by a small current measuring instrument. From one to four batteries can be charged simultaneously. The switch must be set according to number of batteries, and charging current of batteries given by manufacturer must be adjusted. This circuit doesnt measure charging time and charging condition of batteries. Manufacturers give charging time, usually 14-16 h. I solved this problem with a simply, cheap mechanical mains timer. I think its accuracy is sufficient.

Sandor Dobany from Hungary
dsandor@minimail.hu

Tuesday, September 9, 2014

Overload protection for speakers

Although the protection circuit is fairly simple, it forms an effective guard against overload of the input of amplifiers and loudspeakers. Why these inputs may need protection now that line levels have been standardized is because there are signal sources on the market that generate outputs of several volts instead of the standardized 1 V r.m.s. Also, in some applications, the loudspeaker signal is applied to the line output of a separate amplifier via a voltage divider, in which case the levels may be well above 1 V r.m.s. The diagram shows a schematic that resembles the familiar series resistor and zener diode. Here, however, the zener is constructed from a small rectifier and a transistor, since commercial zeners appear to start conducting way below their rated values, which gives rise to unwanted distortion. The constructed zener makes a well-defined limitation possible and does not affect signals below the critical level. Configuring T1 as a diode reduces the number of components needed to a minimum: not even a voltage divider or potentiometer is required. Measurements on the prototype show that the input signal remains virtually undistorted at levels up to 700 mV r.m.s. At the threshold of 1 V r.m.s., the distortion is about 0.02%. Above this level, limiting is welldefined. The peak output voltage of the circuit is about 3 V with an input voltage of about 13 V r.m.s. If the limiting level is required to be slightly higher, consideration should be given to replacing T1 by three or four cascaded diodes.

Monday, September 8, 2014

Dipole Antenna for FM Radio

This is dipole antenna.when you build this you should get the same length.If not you will not be able to get the maximum harvest.Use 60-75 ohm coxial cable.

Note

# when you use insulators becareful.Because if they grounded you cant get goot result

Wednesday, September 3, 2014

Feather Touch Switches For Main

An ordinary AC switchboard contains separate switches for switching ‘on’/’off’ electric bulbs, tube lights, fans, etc. A very simple, interesting schema presented here describes a feather-touch switchboard which may be used for switching ‘on’/‘off’ four or even more devices. The membrane or micro-switches (push-to-on type) may be used with this schema, which look very elegant. By momentary depression of a switch, the electrical appliance will be ‘on’/‘off’, independently. To understand the principle and de-sign of the schema, let us consider an existing switchboard consisting of four switches. One live wire, one neutral wire, and four wires for four switches are connected to the switchboard, as shown in the illustration below the schema diagram.

Feather-Touch Switches For Main Circuit diagram:

Feather Touch Switches For Main Circuit Daigram

The switches are removed and the above-mentioned wires (live, neutral, L1, L2, L3, and L4) are connected to the schema, as shown in the main diagram. The schema comprises four commonly available ICs and four micro-relays, in addition to four micro-switches/membrane switches (push-to-on type) and a few other passive components. IC 7805 is a 5-volt regulator used for supplying 5V to IC2 and IC3 (7476 ICs). These ICs are dual J-K flip-flops. The four J-K flip-flops being used in toggle mode toggle with each clock pulse. The clock pulses are generated by the push-to-on switches S1 through S4 when these are momentarily depressed.

When a switch is momentarily depressed,its corresponding output changes its existing state (i.e. changes from ‘high’ to‘low’ or vice versa) . The outputs of flip-flops drive the corresponding relays, in conjunction with the four relay driver transistors SL100. The wires earlier removed are connected to this schema. On the switch panel board, the micro-switches are connected, and under the board the connections are wired as suggested above. Relays RL1 though RL4 are 9V, SPST-type micro-relays of proper contact ratings.

The schema may be expanded for six switches by using one more IC 7476, and an IC ULN 2004 which has an array of seven Darling-tons for driving the relays. So two more micro-switches and relays may be connected in a similar fashion. This schema can be assembled on a general-purpose PCB and the total cost should not exceed Rs 300. It is suggested that the schema, after assembly on a PCB, may be housed in a box of proper size, which may be fitted on the wall in place of a normal switchboard.

Author :D.K Kaushil - Copyright : EFY mag

Sunday, August 31, 2014

Cheap Electronics Component for Amplifier Application

Cheap electronics component for amplifier application, it is simple to be made for speaker active . The sound quality even this Mini Amplifier TDA2030 quite satisfactory for a portable audio system.

"The series of Mini Amplifier TDA 2030 "The series of mini amplifie can reproduce the power output of 14 Watt with 8 Ohm speaker load. The series of mini-amplifier can be supplied with ource voltage of 12 volts - 15 volts DC. more details, see the following series of pictures.

Daftar komponen
Resistor:

- R1: 150KΩ
- R2: 4.7KΩ
- R3: 100KΩ
- R4: 1Ω 1W
- RA/RB: 100KΩ

Capacitor

- C1: 1µF / 25V
- C2: 2.2µF / 25V
- C3: 100nF
- C4: 22µF / 25V
- C5: 100 µF / 25V
- C6: 220nF
- C7: 2200µF / 35V

IC / Dioda

- IC1: TDA2030 or TDA2030a
- D1/D2: IN4002

Thursday, August 28, 2014

Fan Speed Control for Temperature Wiring diagram Schematic

With this simple schema that you will be able to control the speed of a DC fan according to the temperature measured by a temperature sensor. It is an ideal accessory for your projects that require cooling that are not constant.

This simple design allows precise speed control of motors, fans, and blowers, proportional to the temperature. An NTC thermistor (R1) is used as temperature sensor. A schema optional was added to remotely monitor the operation of the fan and to allow some kind of indication of the approximate speed by increasing the brightness of an LED.

Fan Speed Control for Temperature Circuit Diagram

The R5 must be configured to allow the engine just starting to run at the desired temperature. Any 6K8 between the NTC thermistor 22K can operate provided that the R2 value is one tenth of the thermistor. R6, R7 and D1 are optional: R7 obligation is adjusted until the LED glow dimly when the engine is just running.

Parts List
R1 15K @ 20 ° C NTC Thermistor (See Notes)
R2 1K5 1/4W Resistor (See Notes)
R3 1K 1/4W Resistor
R4 270R 1/4W Resistor 1/2W
R5 22K Trimpots
R6 680R 1/4W Resistor (Optional, see Notes)
R7 470R Trimpots
C1 100μF 25V Electrolytic Capacitor
LED D1 (Optional, any shape and color, see Notes)
Q1 BC547 45V 100mA NPN Transistor
Q2 BD140 80V 1.5A PNP Transistor
M1 Fan Motor 12V 700mA max.

Tuesday, August 26, 2014

RF Transmitter for PIR Sensors Wiring diagram Schematic

This is the Simple RF Transmitter for PIR Sensors Circuit Diagram.

Thursday, August 21, 2014

Simple CD Player Adapter For Car

Whenever Im in the car listening to my favourite CD, it always happens; my batteries go dead. To solve that problem, I built this extremely simple regulator schema. It steps down the 12V from the lighter socket to 9V which is used by the CD player. Different CD players (I have a Sony Discman) may require different voltages, so just use the correct regulator. All the 78xx series regulators have the same pin out, so the schema is universal.

Part       Total Qty.                     Description

C1            1                        1000uF 25V Electrolytic Capacitor
C2                      1              10uF 25V Electrolytic Capacitor
C3            1                        1uF 15V Elextrolytic Capacitor
C4                      1                        0.1uF 15V Electrolytic Capacitor
U1        1                        7809 Or Other Regulator (See "Notes")    See Notes
MISC      1                        Cigarette Lighter Plug, Plug For CD Player (See "Notes"),      Heat Sink For U1, Wire, Case.

Notes

The voltage your CD player needs will determine which regulator you use. For 9V, use the 7809. For 6V, use the 7806. For the unlikely 5V use the 7805. Remember that whatever regulator you use, you will need to heat sink it. The metal case or metal cover on the case makes a great heat sink.
I built the schema in a small case with the long wire to the cigarette lighter plug coming out one end, then another, slightly shorter wire going out the other end to the CD player.

Triple check your wiring. You would hate to ruin an expensive CD player because you reversed one of the connections or hooked the regulator up backwards.

Monday, August 18, 2014

Flasher for bike

Here I like to give you a very useful schema.This is a flasher for your bike this schema can be operated with 6V (4 x1.5 batteries) .You can control flash duration with 5K VR and flash interval can be adj es with 100K

Note

# Build this schema on a PCB

#Use 1.5 x 4 batteries to power this (6V)

Friday, August 15, 2014

Vocal Adaptor for Bass Guitar Amp

These days, music is a major hobby for the young and not-so-young. Lots of people enjoy making music, and more and more dream of showing off their talents on stage. But one of the major problems often encountered is the cost of musical equipment. How many amateur music groups sing through an amp borrowed from a guitarist or bass player?

This is where the technical problems arise not in terms of the .25” (6.3 mm) jack, but in terms of the sound quality (the words are barely understandable) and volume (the amp seems to produce fewer decibels than for a guitar). What’s more, unpredictable feedback may cause damage to the speakers and is very unpleasant on the ear. This cheap little easy-to-build project can help solve these technical problems.

Vocal Adaptor for Bass Guitar Amp-Circuit Diagram

A guitar (or bass guitar) amplifier is designed first and foremost to reproduce the sound of the guitar or bass as faithfully as possible. The frequency response of the amp doesn’t need to be as wide or as flat as in hi-fi (particularly at the high end), and so this sort of amplifier won’t permit faithful reproduction of the voice. If you build an adaptor to compensate for the amp’s limited frequency response by amplifying in advance the frequencies that are then attenuated by the amp, it’s possible to improve the quality of the vocal sound. That’s just what this schema attempts to do.

The adaptor is built around the TL072CN low-noise dual FET op-amp, which offers good value for money. The NE5532 can be used with almost the same sound quality, but at (slightly) higher cost. The schema breaks down into two stages. The first stage is used to match the input impedance and amplify the microphone signal. For a small 15 W guitar or bass amplifier, the achievable gain is about 100 (gain = P1/R1). For more

powerful amplifiers, the gain can be reduced to around 50 by adjusting P1. The second stage amplifies the band of frequencies (adjustable using P2 and P3) that are attenuated by the guitar amp, so as to be able to reproduce the (lead) singer ’s voice as clearly, distinctly, and accurately as possible. To refine the adaptor and tailor it to your amplifier and speaker, don’t be afraid to experiment with the component values and the type of capacitors.

The schema can readily be powered using a 9 V battery, thanks to the voltage divider R4/R5 which converts it into a symmetrical ±4.5 V supply.

Author :Jérémie Hinterreiter