Eight RETRO RADIO Скачать руководство пользователя страница 7 | Manualshive

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Eight RETRO RADIO Скачать руководство пользователя страница 7

Loudspeaker

LM386 amplifier

The

LM386 loudspeaker amplifier

is an integrated circuit (IC)

in a housing with eight pins, numbered from pin 1 at the bot-

tom left corner to pin 8 at the top left corner. Pin 4 (bottom

right) is the negative terminal of the power supply. The ampli

-

fier operates at 9 V and provides 0.5 W to the loudspeaker.

The

loudspeaker

exhibits a resistance of 8 Ohm and can

tolerate up to 0.5 W. The volume depends mainly on how the

loudspeaker is mounted. A pleasant sound is only achieved by
installing the loudspeaker in the housing.

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Содержание RETRO RADIO

Страница 1: ......

Страница 2: ...components and gradually build a complex circuit Finally use the completed FM radio to listen to your local FM station in great sound quality The FM radio is easy to assemble and yet offers many possi...

Страница 3: ...troduction 2 The Components 4 Step 1 Mounting the Amplifier 11 Step 2 Sound Generator 15 Step 3 Improved Amplifier 18 Step 4 Simple Radio 21 Step 5 Tuning 24 Step 6 Mounting in the Housing 27 Troubles...

Страница 4: ...are built on a bread board The centre part contains 46 contact strips with five contacts each The two long strips with 20 contacts along the edges are typically used to provide the operating voltage I...

Страница 5: ...to each other The individual steps are illustrated with assembly drawings photos or circuit diagrams The symbols in the circuit diagrams are as follows FM board Capacitor E capacitor Resistor Potentio...

Страница 6: ...and thus the other components It is important to supply the radio board with an operating voltage of only 3 V It must never be con nected directly to a 9 V battery Instead a voltage regulator is requ...

Страница 7: ...at the top left corner Pin 4 bottom right is the negative terminal of the power supply The ampli fier operates at 9 V and provides 0 5 W to the loudspeaker The loudspeaker exhibits a resistance of 8 O...

Страница 8: ...e to pay attention to the mounting direction as the e cap will be destroyed when the polarity is reversed The negative terminal is the shorter leg it is additionally marked by a white bar The kit cont...

Страница 9: ...he fourth gold ring represents a tolerance of 5 The kit contains four resistors in total 100 brown black brown 1 k brown black red 10 k brown black orange 220 k red red yellow Basically a potentiomete...

Страница 10: ...By turning the axis to the far left the radio is turned off As a special feature of this poten tiometer the resistance curve is not linear but adapted to the human sense of hearing Hence the middle s...

Страница 11: ...th clip Strain relief 100 F e cap LM386 amplifier 1 k resistor brown black red Step 1 Mounting the Amplifier Required components Breadboard LM386 amplifier IC 100 F e capacitor 1 k resistor brown blac...

Страница 12: ...me being Let s start with the first step and insert the compo nents on the breadboard as shown in the illustration Inserting components in the breadboard requires some force The connection wires thus...

Страница 13: ...just fine As most of the components will remain in the same position it already makes sense to install a strain relief for the battery wires at this stage to prevent the battery clip from damage Remov...

Страница 14: ...14...

Страница 15: ...Step 2 Sound Generator Required components 10 k resistor brown black orange 15...

Страница 16: ...f the LM386 is an inverting input When the voltage at this input increases the amplified voltage at the output decreas es In contrast pin 3 does not invert the signal any input signal is amplified at...

Страница 17: ...17...

Страница 18: ...Step 3 Improved Amplifier Required components 100 nF disc capacitor 100 F e capacitor hook up wire 18...

Страница 19: ...radio in this place Pin 3 of the amplifier is now additionally connected to GND This reduces distortions that would otherwise occur by contact resistances on the breadboard Pin 2 of the IC is the amp...

Страница 20: ...20...

Страница 21: ...ep 4 Simple Radio Required components TDA7088 FM IC receiver board HT7530 voltage regulator 10 k resistors brown black orange 1 k resistor brown black red 100 resistor brown black brown hook up wire 2...

Страница 22: ...attached to the positive terminal of the battery and the ground pin right to the negative terminal The output left now provides a stable voltage of 3 V Pay atten tion to the mounting direction The fl...

Страница 23: ...may already be lucky and be able to receive a radio station As the tuning contacts are not yet attached you will receive a random frequency However by momentarily touching the S R and contacts on the...

Страница 24: ...Step 5 Tuning Required components Hook up wire 24...

Страница 25: ...ouch each other Bend the wires so that they make contact when you push them slightly Momentarily touching the push button causes the radio to search for the station of the next higher frequency After...

Страница 26: ...be cut off In this way the minimum frequency of a little lower than 87 5 MHz is set The board contains an additional inte grated capacitor to hold the current tuning voltage By touching the reset push...

Страница 27: ...Step 6 Mounting in the Housing Required components Volume potentiometer tuning potentiometer 220 k resistor red red yellow washers cap nuts hook up wire both rotary knobs radio housing 27...

Страница 28: ...the component from twisting Slide the loudspeaker into the provided bracket You can additionally secure it with a little glue Attach the breadboard between the potentiometers and the loudspeaker At t...

Страница 29: ...29...

Страница 30: ...had been attached The second potentiometer will be used for scanning the frequencies When the potentiometers are attached you can close the housing and control the radio from the outside Compared to...

Страница 31: ...the tuning process An improperly adjusted station will automatically be tuned more precisely While slowly scanning the FM range you will register a certain lock in range where the radio clings to a c...

Страница 32: ...able to receive the more powerful stations clearly First test the radio at low or medium vol ume At full volume clipping at the amplifier might already occur and cause audible distortions Depending on...

Страница 33: ...would point to an improper connection Jiggle the indi vidual wires to track down connection problems Scratching sounds that appear while you lightly touch a wire or a compo nent are caused by imprope...

Страница 34: ...Its volume indicates the voltage Also test the full operating voltage 9 V very loud and the negative connection GND 0 V no sound Further tests should yield the following results BAT pin of the board 3...

Страница 35: ...Measured voltages 35...

Страница 36: ...its are designed to provide reasonable protection against harmful interference in a residential installation This equipment generates uses and can radiate radio frequency energy and if not installed a...

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