Frequency Counter Primer

Frequency counters are easy to use: simply turn on the device and apply the signal to the input. You can use your frequency counter and timer to measure a variety of signals including digital logic signals, radio frequency, and even microwaves. Because of improvements in technology, frequency counters and timers enable you to measure time intervals and frequency, which have an inverse relationship.

You’ll need to apply the signal to the input to measure a time interval or frequency. The next step will be to select the timebase interval, which commonly has the options of point one, one, and ten second(s). These options refer to the time over which the frequency counter gate opens and passing pulses are counted; for example a gate time of one second will count one million pulses for a one megahertz signal or, if five pulses are counted with a gate time of one second, the frequency will be five hertz.

Your frequency counter counts the transition every time the signal passes in the positive direction through the device. More pulses are counted at higher frequencies as you can see from our the example above in which five pulses are counted.

You’ll get more accurate results with longer gate times. Let’s use the previous example with a gate time of point one second for five pulses and a fifty hertz signal. The handheld frequency counter can’t tell the difference between a fifty hertz and fifty-five hertz signal. To get a more accurate reading you can use a one second gate time, thus enabling fifty-five counts for a fifty-five hertz signal.

While longer gate times improve accuracy, your choice of gate time will normally depend on how quickly you need updates for the frequency. Despite the benefits to accuracy longer gate times can slow testing to too great an extent. Because of these tradeoffs in time versus accuracy, you’ll usually use shorter gate times unless you need a high level of accuracy for a particular test.

Multimeter Features Guide

There are a number of different features that differ from one multimeter to the next, some of which you’ll often use and others you may never use.

The most important feature is continuity, which allows you to test whether two things are electrically connected. Continuity testing with a peizo buzzer enables you to determine if your soldering is good, a wire is broken in the middle, and something isn’t connected in addition to allowing you to reverse-engineer or verify a design to a schematic.

Some other important features are resistance testing down to ten ohms or lower and up to one megaohm or higher, direct current voltage testing down to one hundred millivolts or lower and up to fifty volts, alternate current testing down to one volt and up to two hundred volts, and diode testing.

Because it’s easy to forget to turn off your multimeter’s power, auto-off is a great feature to have, which you rarely see on budget multimeters. Regardless of this feature you should get in the habit of turning off your multimeter after you finish using it.

If you know how to use it autoranging is a helpful feature and, typically, autoranging multimeters are of higher quality and have more features than simpler multimeters. Keep in mind that with some systems the current or voltage will be too sporadic for the autorange feature to keep up. Some users dislike autoranging because it slower and less precise.

Other optional but useful multimeter features are alternate and direct current testing, a stand for keeping the multimeter upright, a hold function to keep the maximum value on the screen enabling you to use the probes without staring at the screen, and common battery types (such as a nine volt or AAs).

Back-lit LCD multimeters are nice, but chances are you won’t be measuring circuits in the dark. If you need a multimeter that is visible in low light then by all means look for a back-lit model.

You don’t really need fancy probes for you multimeter — just some sturdy, reasonably-priced ones. Your leads will break down over time, generally at the flex point; however, probes are relatively inexpensive, so when you do break a probe, which you eventually will with enough use, you’ll be able to replace it for around five dollars.

Some features you’ll seldom use include a frequency counter, capacitance testing, inductance testing, duty cycle, transistor beta meter, and temperature probe.