I remember well from when I started in electronics how much money had to be spent on measurement
equipment, e.g. a multimeter or a scope. Today, there are some very interesting devices available
from Chinese suppliers e.g. via Aliexpress or Ebay. Can be very useful for quick measurements/testing
in the amateur radio station, to get new (young) people interested in electronics, etc.
For about $25 you can get the Aneng AN-8008 DMM that has 4 digits (9999 count) and measures
DC and AC (true RMS!) voltage and current, resistance, capacitance, frequency and can even generate
audio tones. It has very low ranges, the least significant digit displays uV or uA on the lowest range.
Very useful, as long as you don't use it to measure dangerous voltages or currents.
I also got a kit for a 200kHz (1 MSPS) single-channel storage scope for less than $25. Takes about 2hrs
to assemble, and you have a pocket size storage scope that I would really have liked to have back in the
days of packet radio, you can have one of them connected to each receiver and see the audio quality
all the time. It can display peak and RMS voltage, frequency etc on-screen.
JYE TECH Digital Oscilloscope DIY Kit (can be found with or without case)
Another nice toy is the M328 LCR-T4 component tester. Based on a design originally published in a
magazine, there are several different versions available that differ in connections and if it does/does
not include a case. I have one that uses a ZIF socket for the connection. It has 3 test terminals and
you can connect a transistor, fet, triac, resistor, capacitor, inductor, diode, zener etc to the test terminals
and it will display the type of component, pinout, and value on the LCD screen. Includes other useful info
like the ESR of a capacitor, capacitance of a diode, etc. Can be found for less than $10.
Of course it all isn't professional test equipment, but it is a lot of fun for the money if you ask me...
Rob