Electrical equipment troubleshooting, open circuit, short circuit, parallel inspection method - Database & Sql Blog Articles

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The open-circuit method, also known as the isolation or split-test technique, involves disconnecting a suspected section of the circuit from the rest of the system. This allows the rest of the circuit to continue functioning normally while testing whether the fault disappears. If the issue goes away, it strongly suggests that the problem lies within the isolated section. This approach is particularly useful in complex systems where isolating components can help narrow down the root cause efficiently.

Some electrical circuits are highly intricate, involving numerous components and interdependent units. In such cases, using the open-circuit method becomes essential. For example, in closed-loop systems like logic control circuits, where multiple units are connected in sequence, a failure in one part can affect the entire system. By applying the segmentation method—disabling or isolating parts of the circuit—it becomes easier to identify which component or section is causing the malfunction. This technique is especially effective for power failures with multiple loads, where individual branches or components can be tested separately to determine their impact on the overall performance.

The short-circuit check method is another valuable diagnostic tool. It involves using a shorting clamp (for DC) or a capacitor clamp (for AC) to temporarily short a specific part of the circuit. By observing changes in image, sound, or voltage, technicians can quickly detect faults such as noise, interference, ripple, or self-oscillation. For instance, when troubleshooting a TV set, connecting a 100pF capacitor clamp to the SAWF (Surface Acoustic Wave Filter) can reveal if the component is faulty—if the picture improves, the SAWF is likely damaged. Similarly, shorting an input terminal to ground may eliminate interference, indicating the fault is located upstream. The capacitance value used depends on the circuit’s operating frequency, with higher frequencies typically requiring smaller capacitors for accurate results.

The parallel detection method is a non-invasive technique where a known good component, or one with similar specifications, is connected in parallel with a suspect component. This method avoids the need to desolder or remove parts, making it ideal for quick checks. For example, when diagnosing a color TV with a multimeter, it can be difficult to detect an open-circuit small capacitor. By paralleling it with a known good capacitor, if the fault disappears, it confirms the original component is defective. If no improvement is seen, the suspect component is ruled out. This method is also useful for checking variable capacitors in loop circuits, allowing technicians to adjust and determine the required capacitance. For resistive failures, such as degraded or open resistors, a parallel resistance test can help identify the issue without dismantling the circuit.

In conclusion, the open-circuit, short-circuit, and parallel methods each offer unique advantages in identifying and resolving circuit faults. Whether it's isolating a section, simulating a short, or testing in parallel, these techniques are essential tools in any technician’s arsenal. Combining them with experience and logical reasoning ensures efficient and accurate troubleshooting in both simple and complex electronic systems.