1. Testing LEDs
Testing LEDs is as simple as performing a basic continuity test, right? – Actually, it’s not.
To test an LED, you need to provide current in the right direction and in the right amount. Too little and the LED won’t allow any current to pass, making it appear to be dead, too much and the LED could be damaged. Current applied in the wrong direction, will also yield no results.
A typical multi-meter in continuity test mode does not provide enough current (known as forward bias) to drive an LED, so will typically ‘fail’ a basic continuity test on a good LED. If the meter features a specific LED test mode, then it may work but will require you to know the LED’s polarity and most multi-meter LED test modes are only suitable for testing single LEDs – many partwork components have two or more LEDs on the same circuit. Most multimeters have a maximum voltage that their LED test mode can support (often 2.8v), this means that some LEDs cannot be tested if they require a higher forward voltage.
LED short circuits
A failed LED could pass a multi-meter test if it fails to a short circuit. A continuity test would see this as a pass when in fact the LED would not illuminate when used and could damage your model’s circuit board.
Could I not just connect my LED to a battery?
This is not recommended as LEDs are damaged if they draw too much current. If connected directly to a battery without a resistor, the LED could be permanently damaged. Having to calculate the resistor value and connect it to the LED before testing is not practical (assuming you even have resistors to hand!).
How is the Test Circuit Pro different?
The Test Circuit Pro automatically detects when an LED is connected and supplies the correct amount of current to test the LED without damaging it or getting a false result. Not too much, not too little.
Flashing LEDs
Some LEDs are designed to flash and have flashing circuitry built in. The Test Circuit Pro can also test these LEDs unlike a multimeter which often can’t if the flashing circuit requires a specific current or forward voltage.
2. Testing Speakers
When testing speakers, a multimeter can measure resistance to confirm the coil is intact, but this only gives a partial picture of the speaker’s condition.
The purpose-built tester on the Test Circuit Pro goes further by generating an audio signal to check sound output and detect distortion. This allows you to evaluate both electrical and acoustic performance, which a multimeter cannot achieve.
3. Testing Batteries
A multimeter can measure a battery’s voltage, but it cannot accurately assess its capacity or ability to deliver power under load.
Voltage readings alone can be misleading, as a seemingly charged battery may fail when current is drawn. The Test Circuit Pro simulates load conditions, measuring internal resistance, and providing a more detailed capacity analysis, offering a more comprehensive evaluation of battery health. By comparing the battery’s voltage under load to a 4.5v reference voltage, the Test Circuit Pro is also significantly more accurate than most unpowered battery testers.
4. Testing Motors
Testing motors with a multimeter is often limited to checking resistance across windings to identify open or short circuits.
However, this doesn’t reveal issues like weak magnets, uneven winding distribution, jammed commutators, or gearbox faults. The Test Circuit Pro goes beyond resistance measurements by applying voltage to observe motor rotation, managing starting torque, and uses a dedicated motor controller to manage power performance under load and includes thermal cutout protection to protect your power supply from a motor with a short circuit. These capabilities make diagnosing motor health and performance more comprehensive, safe and reliable than a multimeter alone can offer.
5. Manual Effort and Time
Using a multimeter to test components often requires manual interpretation, careful range selection, and additional steps to gather meaningful results.
For example, checking an LED’s characteristics may require adding resistors or external power sources. Purpose-built testers such as the Test Circuit Pro simplify the process, delivering quick, easy to interpret results for multiple component types.
6. Plugs and Probes!
Testing components with a multimeter probes can be a fiddly business, especially if the component is connected to a plug (like partwork components are).
Being able to directly connect the component to the Test Circuit Pro provides reliable and simple connection for testing and reliable test results.
The Test Circuit Pro also makes testing tiny LEDs that are mounted on circuit boards a breeze!
7. Risk of Misinterpretation
When testing LEDs, speakers, or batteries, misinterpreting a multimeter’s readings can lead to incorrect conclusions about a component’s functionality and health.
The Test Circuit Pro reduces this risk by providing clear, easy to understand results and includes visual and audible confirmations for added clarity.
Conclusion
While multimeters remain an invaluable tool for general electrical measurements, their limitations in testing LEDs, speakers, and batteries make diagnostics less efficient and precise without significant technical knowledge and a detailed understanding of the component’s technical specifications.
Purpose-built component testers like the Test Circuit Pro, with their specialised capabilities, offer a faster, more accurate, and user-friendly alternative, making them a worthwhile investment for those frequently working with these components.
Importantly, the Test Circuit Pro can be used by anyone, regardless of their previous experience with electronics, helping keep your components safe from accidental damage.
