Kapasitor

Macam-Macam Kapasitor

Jenis Kapasitor Berdasarkan Polaritasnya

Kapasitor Nonpolaritas Kapasitor ini tidak mempunyai kaki positif dan negatif sehingga cara pemasangan pada rangkaian elektronika boleh bolak-balik. Yang termasuk kapasitor ini adalah kapasitor mika, kapasitor keramik,kapasitor kertas, dan kapasitor milar.<span class="fullpost">
Kapasitor Polaritas Kapasitor ini mempunyai kaki positif dan negatif, sehingga cara pemasangan pada rangkaian elektronika tidak boleh terbalik.
Variabel Condensator ( Varco ) Kondensator ini dapat diatur dengan cara memutar rotor (as) yang ada pada badan komponen.
Kondensator Trimer Kondensator ini dapat diatur dengan cara memutar rotor (as) yang ada pada badan komponen, tetapi harus mengunakan  obeng.

Kapasitor Berdasarkan Bahan Penyekat Konduktor ( Dielektrikum)

Kapasitor Keramik

Kapasitor Tantalum

 

Kapasitor Inti udara

Kapasiitor Elektrolit

Kapasitor Kertas

Kapasitor Mika / Milar

Kapasitor Polyester

Tipe Kapasitor berdasarkan Dielektrikum

1.	Variabel Condensator ( varco ) Kondensator ini dipakai untuk tuning atau mencari gelombang radio. Jenis ini mempunyai udara sebagai dielektrikum.Kapasitor variabel mempunyai pelat-pelat yang stasioner (stator) dan pelat-pelat yang digerakkan (rotor ), biasanya terbuat dari alumunium. Dengan memutar tombol, luas plat yang berhadapan dapat diatur sehingga kapasitas kapasitor dapat diubah-obah. Dengan mengubah kapasitor frekuensi dapat distel.
2.	Kapasitor Keramik Kapasitor ini menpunyai dielektrikum keramik. Kapasitor ini mempunyai oksida logam dan dielektrikumnya terdiri atas campuran titanium-oksida dan oksida lain. Kekuatan dielektrikumnya tinggi dan mempunyai kapasitas besar sekali dalam ukuran kecil.
3.	Kapasitor Kertas Kapasitor ini mempunyai dielektrikum kertas dengan lapisan kertas setebal 0,05-0,02 mm antara dua lembar kertas alumunium.Kertasnya diresapi dengan minyak mineral untuk memperbesar kapasitas dan kekuatan dielektrikumnya.
4.	Kapasitor Mika Kapasitor ini mempunyai elektroida logam dan lapisan dielektrikum dari polysteryne mylar dan teflon setebal 0,0064 mm. Digunakan untuk koreksi faktor daya. Seperti uji visi nuklir
5.	Electrolit Condensator( Elco ) Kapasitor ini mempunyai dielektrik oksida alumunium dan sebuah elektrolit sebagai elektroda negatif. Elektroda postif terbuat dari logam seperti alumunium dan tantalum tetapi sebuah elektroda negatif terbuat dari elektrolit. Tebal lapisan oksidanya adalah 0,0001. Dalam rangkaian elektronika sebagai perata denyut arus listrik.

Tabel Nilai Dielektrikum

Bahan	Angka dieklektrikum
Hampa	1
Udara/gas lain	1
Air suling	80
Kertas farafin	2,2
Mika	5,5-7
Porselen	5,5
Tantalum	27
Olie paranol	4,5
Olie silikon	2,8
Teflon	20
Keramik	5-100

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Photo Electric Street Light

This is basically a Schmitt Trigger circuit which receives input from a cadmium sulfide photo cell and controls a relay that can be used to switch off and on a street lamp at dawn and dusk. I have built the circuit with a 120 ohm/12 volt relay and monitored performance using a lamp dimmer, but did not connect the relay to an outside light.
The photo cell should be shielded from the lamp to prevent feedback and is usually mounted above the light on top of a reflector and pointed upward at the sky so the lamp light does not strike the photo cell and switch off the lamp.
The photo cell is wired in series with a potentiometer so the voltage at the junction (and base of transistor) can be adjusted to about half the supply, at the desired ambient light level. The two PNP transistors are connected with a common emitter resistor for positive feedback so as one transistor turns on, the other will turn off, and visa versa. Under dark conditions, the photo cell resistance will be higher than the potentiometer producing a voltage at Q1 that is higher than the base voltage at Q2 which causes Q2 to conduct and activate the relay.
The switching points are about 8 volts and 4 volts using the resistor values shown but could be brought closer together by using a lower value for the 7.5K resistor. 3.3K would move the levels to about 3.5 and 5.5 for a range of 2 volts instead of 4 so the relay turns on and off closer to the same ambient light level. The potentiometer would need to be readjusted so that the voltage is around 4.5 at the desired ambient condition. Read More..

LED Traffic Lights

The LED traffic Light circuit controls 6 LEDs (red, yellow and green) for both north/south directions and east/west directions. The timing sequence is generated using a CMOS 4017 decade counter and a 555 timer. Counter outputs 1 through 4 are wire ORed using 4 diodes so that the (Red - North/South) and (Green - East/West) LEDs will be on during the first four counts. The fifth count (pin 10) illuminates (Yellow - East/West) and (Red - North/South). Counts 6 through 9 are also wire ORed using diodes to control (Red - East/West) and (Green - North/South). Count 10 (pin 11) controls (Red - East/West) and (Yellow - North/South). The time period for the red and green lamps will be 4 times longer than for the yellow and the complete cycle time can be adjusted with the 47K resistor. The eight 1N914 diodes could be subsituted with a dual 4 input OR gate (CD4072). Read More..

Line Powered White LEDs

The LED circuit below is an example of using 25 white LEDs in series connected to the 120VAC line. It can be modified for more or less LEDs by adjusting the resistor value. The exact resistance will depend on the particular LEDs used. But working out the resistor value is a bit complicated since current will not continously flow through the resistor.
In operation, the output of the bridge rectifier will be about 120 DC RMS or 170 volts peak. If we use 25 white LEDs with a forward voltage of 3 volts each, the total LED voltage will be 75 volts. The peak resistor voltage will be 170- 75 or 95 volts but the resistor voltage will not be continous since the input must rise above 75 before any current flows. This (dead time) represents about 26 degrees of the 90 degree half wave rectified cycle, (asin) 75/170 = (asin) .44 = 26 degrees. This means the resistor will conduct during 90-26 = 64 degrees, or about 71 percent of the time.
Next we can work out the peak LED current to determine the resistor value. If the LED current is 20mA RMS, the peak current will be 20*1.414 or 28mA. But since the duty cycle is only 71 percent, we need to adjust this figure up to 28/0.71 = 39mA. So, the resistor value should be 95/.039 = 2436 ohms (2.4K) and the power rating will be .02^2 *2400= .96 watts. A two watt size is recommended.
Now this circuit can also be built using 2 diodes and resistor as shown in the lower drawing. The second diode in parallel with the LEDs is used to avoid a reverse voltage on the LEDs in case the other diode leaks a little bit. It may not be necessary but I thought it was a good idea.
Working out the resistor value is similar to the other example and comes out to about half the value of the full wave version, or about 1.2K at 1 watt in this case. But the peak LED current will be twice as much or about 78mA. This is probably not too much, but you may want to look up the maximum current for short duty cycles for the LEDs used and insure 79mA doesn't exceed the spec. Read More..

AC Line powered LEDs

The circuit below illustrates powering a LED (or two) from the 120 volt AC line using a capacitor to drop the voltage and a small resistor to limit the inrush current. Since the capacitor must pass current in both directions, a small diode is connected in parallel with the LED to provide a path for the negative half cycle and also to limit the reverse voltage across the LED. A second LED with the polarity reversed may be subsituted for the diode, or a tri-color LED could be used which would appear orange with alternating current. The circuit is fairly efficient and draws only about a half watt from the line. The resistor value (1K / half watt) was chosen to limit the worst case inrush current to about 150 mA which will drop to less than 30 mA in a millisecond as the capacitor charges. This appears to be a safe value, I have switched the circuit on and off many times without damage to the LED. The 0.47 uF capacitor has a reactance of 5600 ohms at 60 cycles so the LED current is about 20 mA half wave, or 10 mA average. A larger capacitor will increase the current and a smaller one will reduce it. The capacitor must be a non-polarized type with a voltage rating of 200 volts or more.
The lower circuit is an example of obtaining a low regulated voltage from the AC line. The zener diode serves as a regulator and also provides a path for the negative half cycle current when it conducts in the forward direction. In this example the output voltage is about 5 volts and will provide over 30 milliamps with about 300 millivolts of ripple. Use caution when operating any circuits connected directly to the AC line.

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1.5 Volt LED Flashers

The LED flasher circuits below operate on a single 1.5 volt battery. The circuit on the upper right uses the popular LM3909 LED flasher IC and requires only a timing capacitor and LED.
The top left circuit, designed by Andre De-Guerin illustrates using a 100uF capacitor to double the battery voltage to obtain 3 volts for the LED. Two sections of a 74HC04 hex inverter are used as a squarewave oscillator that establishes the flash rate while a third section is used as a buffer that charges the capacitor in series with a 470 ohm resistor while the buffer output is at +1.5 volts. When the buffer output switches to ground (zero volts) the charged capacitor is placed in series with the LED and the battery which supplies enough voltage to illuminate the LED. The LED current is approximately 3 mA, so a high brightness LED is recommended.
In the other two circuits, the same voltage doubling principle is used with the addition of a transistor to allow the capacitor to discharge faster and supply a greater current (about 40 mA peak). A larger capacitor (1000uF) in series with a 33 ohm resistor would increase the flash duration to about 50mS. The discrete 3 transistor circuit at the lower right would need a resistor (about 5K) in series with the 1uF capacitor to widen the pulse width.

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Generating -5 Volts From a 9 Volt Battery

A 555 timer can be used to generate a squarewave to produce a negative voltage relative to the negative battery terminal. When the timer output at pin 3 goes positive, the series 22 uF capacitor charges through the diode (D1) to about 8 volts. When the output switches to ground, the 22 uF cap discharges through the second diode (D2) and charges the 100 uF capacitor to a negative voltage. The negative voltage can rise over several cycles to about -7 volts but is limited by the 5.1 volt zener diode which serves as a regulator. Circuit draws about 6 milliamps from the battery without the zener diode connected and about 18 milliamps connected. Output current available for the load is about 12 milliamps. An additional 5.1 volt zener and 330 ohm resistor could be used to regulate the +9 down to +5 at 12 mA if a symmetrical +/- 5 volt supply is needed. The battery drain would then be around 30 mA.

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555 Tone Generator (8 ohm speaker)

This is a basic 555 squarewave oscillator used to produce a 1 Khz tone from an 8 ohm speaker. In the circuit on the left, the speaker is isolated from the oscillator by the NPN medium power transistor which also provides more current than can be obtained directly from the 555 (limit = 200 mA). A small capacitor is used at the transistor base to slow the switching times which reduces the inductive voltage produced by the speaker. Frequency is about 1.44/(R1 + 2*R2)C where R1 (1K) is much smaller than R2 (6.2K) to produce a near squarewave. Lower frequencies can be obtained by increasing the 6.2K value, higher frequencies will probably require a smaller capacitor as R1 cannot be reduced much below 1K. Lower volume levels can be obtained by adding a small resistor in series with the speaker (10-100 ohms). In the circuit on the right, the speaker is directly driven from the 555 timer output. The series capacitor (100 uF) increases the output by supplying an AC current to the speaker and driving it in both directions rather than just a pulsating DC current which would be the case without the capacitor. The 51 ohm resistor limits the current to less than 200 mA to prevent overloading the timer output at 9 volts. At 4.5 volts, a smaller resistor can be used.

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Cara memperbaiki Lemari Es / Kulkas

Apabila lemari es di rumah anda tidak bisa dingin maka solusinya adalah seperti berikut ini:
Bagian  yang pertama yang harus  diperiksa adalah apakah lampu penerangan ruang kulkas, saat pintu ruangan kulkas dibuka, menyala atau  padam. Apakah menyala ?
Kalau tidak menyala, maka berarti listrik tidak masuk ke kulkas anda, bisa karena steker kulkas tidak masuk dengan benar ke stop kontaknya. Periksa dan perbaiki.

Kalau ya menyala, berarti listrik sudah masuk ke kulkas dan sekarang dengarkan atau pegang dengan lap, kompresornya, yaitu bagian yang berwarna hitam, berbentuk silinder besar, di belakang kulkas.

Kalau tidak ada suara atau getaran, berarti tegangan listrik tidak masuk ke motor kompresor kulkas anda. Bisa karena motor Timer tidak bekerja (kalau kulkasnya sistim No Frost), ada kabel putus antara lain digigit tikus atau Thermostat, yaitu setelan dingin yang ada di dalam ruang kulkas, rusak atau karena sesuatu hal, motor kompresor bermasalah dan diputuskan untuk mencegah semakin rusak dengan Overload Protektor yang berbentuk benjolan, menempel pada kompresor.

Untuk kasus ini, periksa apakah ada kabel yang putus antara lain digigit tikus. Kalau mampu dan mempunyai voltmeter, lepaskan Overload Protektor dan ukur tegangan yang masuk ke kompresor, apakah tegangan masuk atau tidak.

Kalau tegangan tidak masuk, periksa Timernya dan Thermostatnya atau hubung singkatkan dahulu secara langsung untuk pemeriksaan dan kalau kompresor bekerja, itu berarti Timer atau Thermostat tidak bekerja dan harus diganti.

Kalau ada suara dan getaran, namun tetap tidak dingin, berarti pada sistim tertutupnya, ada kebocoran, sehingga Freon, bahan yang fungsinya mendinginkan Evaporator, habis.

Untuk kasus ini, maka tidak ada jalan lain, harus membawa lemari es kita ke tukang servis profesional. Sebab kalau kita tangani sendiri bisa bisa  kerusakannya justru lebih parah. Betul kan ??

Gambar lengkap bagian-bagian Kulkas

Sumber : Modul PPRT Vedc Read More..

Cara memperbaiki Penghisap debu ( Vacuum Cleaner )

Vacum Cleaner sering mengalami kerusakan dengan gejala mati sama sekali/ tidak bisa menghisap. Cara memperbaikinya adalah dengan memeriksa
1. Motor listriknya, bila masih baik ;
2. Periksa kabel daya, ukur dengan ohm meter konduksivitas kabel, bila masih baik
3. Periksa sekring ( thermo fuse ), biasanya ini yang sering rusak. Bila benar-benar rusak ganti dengan yang baru.

Gambar Bagian-bagaian Vacuum Cleaner

Sumber : Modul PPRT Vedc Read More..

Memperbaiki Rice Cooker

Bila rice cooker tidak bisa dipakai untuk memasak maka periksalah kabel dayanya, bila putus gantilah.  Periksa juga elemen pemanasnya dengan ohm meter. Bila tahanannya menunjukkan harga tak terhingga berarti elemen putus, gantilah dengan yang baru yang sesuai dengan aslinya. Read More..

Cara memperbaiki Blender

Apa bila blender di rumah anda rusak maka cara memperbaikinya adalah sebagai berikut:
1. Bila blender tidak bisa berputar maka periksalah kabel daya, sekring, saklar dan motornya.

Bila ada yang menunjukan gejala rusak, perbaiki atau ganti komponen dengan yang baru Read More..

Cara memperbaiki Hair Dryer

Apabila hair dryer  anda mengalami rusak maka cara untuk memperbaikinya adalah seperti langkah-langkah berikut:
1. Lepaskan hair dryer dari sumber listrik

2. Ukurlah resistansi kabel daya, bila menunjukkan tak terhingga berarti kabel putus, gantilah dengan yang baru atau sambung bagian yang putus.
3. Periksa motor listrik
4.Periksa resistansi kawat pemanas, bila masih baik akan menunjukkan nilai tertentu. Bila tak terhingga berarti putus. Sambung bagian yang putus atau ganti dengan yang baru. Read More..