Punjab PSEB Matric NSQF Electronics case studies
Punjab PSEB Matric NSQF Electronics · Put your knowledge to work in context.
The Punjab School Education Board (PSEB) Matriculation (Class 10) NSQF examination is the board-level assessment route for Class 10 candidates in Punjab who take National Skills Qualification Framework vocational subjects alongside their general subjects. This page covers the Electronics trade. The Punjab PSEB Matric NSQF Electronics case studies are 5 cases and about 3,051 words.
1LM7812 supply sags only under load: regulator or headroom?
A trainee at a PSEB NSQF electronics workshop assembles a fixed 12 V, 0.75 A regulated supply: a 230 V/14 V, 1 A transformer, a four-diode bridge (1N4007), a single 1000 µF/25 V filter capacitor, and an LM7812 with a small clip-on heatsink. On the bench the unloaded output measures 11.95 V, which looks perfect.
610 words, about 3 min2CE amplifier saturates on one board: transistor batch or base divider?
Students build a single-stage common-emitter amplifier on breadboard: Vcc = 12 V, R1 = 47 kΩ from Vcc to base, R2 = 10 kΩ from base to ground, Rc = 2.2 kΩ, Re = 470 Ω bypassed by 100 µF, input 10 mV peak-to-peak at 1 kHz through a 10 µF capacitor, transistor BC547 with β ≈ 150. The lab sheet expects Vb ≈ 2.1 V, Ve ≈ 1.4 V, Vc ≈ 5.4 V and a clean inverted output of about 1 V peak-to-peak.
647 words, about 3 min3Dim, flickering LED lamp: wrong dropper capacitor and missing bleed resistor
An NSQF batch assembles 15 identical LED lamps: 12 white LEDs in series (3.2 V each, 20 mA), a 0.33 µF/400 V metallised polyester dropper capacitor, a 100 Ω series resistor, a 1N4007 bridge, a 470 µF/63 V reservoir, a 1 MΩ bleed resistor across the dropper, all in a sealed plastic box fed from a two-pin 230 V plug. Design current is about 20 mA.
613 words, about 3 min4555 astable reads 1.25 kHz on the CRO but 1.00 kHz on the counter
A trainee checks a 555 astable board built to a lab sheet: R1 = 10 kΩ, R2 = 68 kΩ, C = 10 nF, Vcc = 9 V, pin 5 decoupled with 10 nF, output on pin 3. The calculated frequency is about 1 kHz.
562 words, about 3 min5Tingling soldering station: open protective earth, not a short circuit
A PSEB workshop has eight soldering stations on one bench, each with a metal chassis and a 3-pin 6 A socket. Students report a tingling sensation when touching the chassis of station no.
619 words, about 3 min