What Is a Handy Oscilloscope?
A handy oscilloscope is a small oscilloscope designed for outdoor use and can be operated by batteries.
An oscilloscope is a measuring instrument that displays changes in signal voltage in an electronic circuit as time-series waveform data. By reading the changes in this waveform and the magnitude of the amplitude, changes in the signal are measured. Originally designed for use in laboratories and on factory production lines, these devices require high precision, high sensitivity, high-speed data processing, and other high performance features, resulting in a large chassis and high power consumption.
On the other hand, oscilloscopes are also needed for use in the field where electronic equipment is installed for adjustment and repair of the equipment. In this case, even if the performance is somewhat inferior, the oscilloscope must be small, lightweight, and battery-powered, eliminating the need for a commercial power supply. A handy oscilloscope satisfies these requirements.
Uses of Handy Oscilloscopes
As noted in the previous section, the primary use of a handy oscilloscope is for waveform observation at the site where the equipment is installed. The small size and the fact that it does not require a power supply make it easy to maneuver, easy to use, and increases work efficiency.
Also, because it is battery-powered, it is suitable for waveform observation of equipment in a floating state. However, if the ground level of the device to which the oscilloscope is connected is not fixed and the oscilloscope is in a floating state, there is a possibility of a large potential difference between the two, which may damage the device or the oscilloscope. With battery operation, the handy oscilloscope side is also in a floating state, so such problems do not occur.
Furthermore, handy oscilloscopes are also used by individuals for their electronic work because of their relatively simple and inexpensive functions. Similarly, they are easy to use in classes at educational institutions.
Principle of the Handy Oscilloscopes
There are two types of oscilloscopes: an analog type that uses the afterimage effect of a cathode-ray tube, and a digital type that converts the signal waveform to A/D and records it in memory. All handy oscilloscopes are digital types.
Therefore, the principle of capturing signal waveforms is exactly the same as that of digital oscilloscopes. However, because they are small and battery-powered, there are many limitations in terms of functionality. The main limitations are as follows:
- Small waveform memory capacity
- Waveform sampling frequency cannot be increased to high speed
- Limited accessories such as probes
- Limited number of channels (most models have a 2-channel configuration, few have more)
- Complex trigger conditions cannot be set
On the other hand, because it is battery-powered, the ground level can be set independently of the ground as described in the previous section, so an ordinary probe can be used even in situations where a differential probe is required with an ordinary oscilloscope.
Types of Handy Oscilloscopes
Miniaturized handy oscilloscopes are available in the following types:
1. Type That Converts a PC Into an Oscilloscope
This type is a digitizer that converts signals to A/D and stores them in memory, and is connected to a PC via USB. This type is generally simple and inexpensive, but it is not strictly speaking a handy device, since a PC is indispensable for waveform observation.
2. All-In-One Type
This type is equipped with a display device and is capable of capturing signal waveforms and displaying waveforms independently. The captured signal waveforms can be output to an external device via USB or a memory card, and the data can be analyzed using a PC. In addition, the built-in rechargeable battery allows measurement without connecting to a commercial power source, as long as the battery is charged with an AC adapter. Some models can use commercially available alkaline batteries.
3. Type With Digital Multimeter Function
In addition to the functions of an oscilloscope, it integrates the functions of a digital multimeter and a frequency counter. Although the individual functions are not as good as those of dedicated measuring instruments, the single unit provides a complete set of measurement functions, making it extremely convenient, especially when brought to the site where the equipment is installed for measurement.