Monday, November 22, 2021

DPDT Knife Switch: Function, Common Mistakes & SPM Physics Amali Tips







👀 Cara Membaca | Reading Technique

✅ Perhatikan kedudukan tuil suis sebelum merekod keadaan litar.

Observe the switch lever position before recording the circuit condition.

✅ Pastikan suis berada sepenuhnya pada satu sisi dan membuat sentuhan yang baik dengan terminal.

Ensure the switch is fully engaged on one side and makes proper contact with the terminals.

✅ Semak perubahan bacaan meter selepas suis ditukar kedudukan.

Check for changes in meter readings after switching positions.


❌ Common Mistakes

❌ Menganggap kedua-dua kedudukan suis menghasilkan litar yang sama.

Assuming both switch positions produce the same circuit configuration.

❌ Sambungan wayar pada terminal yang salah.

Connecting wires to the wrong terminals.

❌ Tidak menyemak kedudukan suis sebelum mengambil bacaan.

Failing to check the switch position before recording readings.


⚠️ Safety / Handling

⚠️ Matikan bekalan kuasa sebelum menukar sambungan wayar.

⚠️ Switch off the power supply before changing wire connections.

⚠️ Pastikan terminal bersih dan tidak longgar.

⚠️ Ensure the terminals are clean and securely tightened.

⚠️ Jangan menukar kedudukan suis dengan kasar kerana boleh merosakkan kenalan logam.

⚠️ Do not force the switch lever as it may damage the metal contacts.


🎯 SPM Exam Tip

📌 DPDT sering digunakan untuk menukar arah arus dalam gegelung motor atau galvanometer.

📌 A DPDT switch is commonly used to reverse the direction of current in a motor coil or galvanometer.

📌 Dalam eksperimen fizik, perubahan kedudukan suis boleh menyebabkan arah pesongan galvanometer berubah.

📌 In physics experiments, changing the switch position may reverse the galvanometer deflection.

📌 Ingat: Double Pole = dua litar, Double Throw = dua pilihan sambungan.

📌 Remember: Double Pole = two circuits, Double Throw = two switching positions.

 

Sunday, November 14, 2021

Gold Leaf Electroscope

This instrument is used for the detection of charge and measuring
static electricity.It works on the principle that the like charges repel
each other.


 

Static and Kinetic Friction


Static friction is what keeps the box from moving without being pushed, and it must be overcome with a sufficient opposing force before the box will move. Kinetic friction (also referred to as dynamic friction) is the force that resists the relative movement of the surfaces once they're in motion.

 

SLOTTED SET OF MASSES AND HANGER. Set of 9 slotted masses, one hanger






 

A Pulley as a Simple Machine



A pulley is a simple machine consisting of a wheel turning on an axle. Pulleys are often used singly and in combinations to do work.

 

Saturday, November 6, 2021

Measuring a Resistor with a Digital Multimeter: Reading Technique & SPM Physics Tips


1K resistor


200 ohms resistor

Perintang (resistor) ialah komponen elektronik yang digunakan untuk menghadkan aliran arus elektrik dalam litar. Nilai rintangannya diukur dalam unit ohm (Ω).

A resistor is an electronic component used to limit the flow of electric current in a circuit. Its resistance is measured in ohms (Ω).


👀 Cara Membaca | Reading Technique

✅ Pilih mod Resistance (Ω) pada multimeter.

Select the Resistance (Ω) mode on the multimeter.

✅ Sentuhkan probe hitam dan probe merah pada kedua-dua kaki resistor.

Touch the black and red probes to the two resistor leads.

✅ Tunggu sehingga bacaan menjadi stabil sebelum direkodkan.

Wait until the reading becomes stable before recording it.

✅ Pastikan resistor tidak disambungkan kepada bekalan kuasa semasa pengukuran.

Ensure the resistor is not connected to a power supply while measuring.


❌ Common Mistakes

❌ Mengukur resistor semasa litar masih hidup.

Measuring a resistor while the circuit is still powered.

❌ Memilih julat Ω yang tidak sesuai.

Selecting an unsuitable resistance range.

❌ Menyentuh kedua-dua kaki resistor dengan jari semasa pengukuran.

Touching both resistor leads with your fingers during measurement.

❌ Menganggap nilai resistor mesti tepat sama seperti nilai yang tertera.

Assuming the measured value must be exactly the same as the labelled value.


⚠️ Safety / Handling

⚠️ Matikan bekalan kuasa sebelum mengukur nilai resistor.

⚠️ Switch off the power supply before measuring resistance.

⚠️ Elakkan membengkokkan kaki resistor secara berlebihan.

⚠️ Avoid bending the resistor leads excessively.

⚠️ Simpan resistor dalam bekas yang sesuai selepas digunakan.

⚠️ Store resistors properly after use.


🎯 SPM Exam Tip

📌 Resistansi diukur dalam unit ohm (Ω).

📌 Resistance is measured in ohms (Ω).

📌 Nilai sebenar resistor mungkin sedikit berbeza daripada nilai nominal.

📌 The actual resistance may differ slightly from the nominal value.

Example from the Photo

✅ Resistor 1 kΩ

Multimeter Reading: 1007 Ω

✅ Resistor 220 Ω

Multimeter Reading: 219.6 Ω

📌 Perbezaan kecil ini adalah normal kerana toleransi pembuatan.

📌 Small differences are normal due to manufacturing tolerance.


🧠 SPM Concept Check

📌 Semakin besar nilai resistor:

📌 The higher the resistance:

✅ Semakin sukar arus mengalir.

The more difficult it is for current to flow.

✅ Semakin kecil arus dalam litar.

The smaller the current in the circuit.

Ohm's Law

V = IR

Where:

  • V = Voltage / Voltan
  • I = Current / Arus
  • R = Resistance / Rintangan



 

Tuesday, November 2, 2021

Cable Peeler - kabel abisolierung




 

Foward current in diode.





A diode is a semiconductor device that essentially acts as a one-way switch for current. It allows current to flow easily in one direction, but severely restricts current from flowing in the opposite direction.

 

Heat - Bar and Gauge


After heating, the gauge shows that the bar has increased in length, which is called linear expansion

 

Sanwa Analog Multitesters YX360TRD



Case and instrument in one body, convenience to carry and store.