08/22/2024:  This page is a work in progress and I will add home-made test equipment as soon as I can.

Ideas and submissions are most welcome!

The Octopus – oops, it has 9 legs, not 8:  Forrest Cook, W0RIO, provides an article regarding how to build and use the “Octopus,” which is a curve tracer for use in conjunction with any oscilloscope.  It is suitable for testing a wide variety of electronic components both in-circuit and out-of-circuit.  It is easy to construct and is very useful for finding defective semiconductors and other components.  It is a circuit that has been around since at least the 1960’s and gets its name from the  numerous wires that come out of the box.  The page opened by the “Octopus” link above contains four other links that provide improvements, updates and additional capabilities for this versatile circuit.

Need to measure an unknown capacitor (not an electrolytic)?  K8JWR (SK) provides a simple circuit for doing this.

Need to measure an unknown inductor?  Hot Iron #3 shows an easy way to do it.  Simply combine a known variable capacitor in parallel with the unknown inductance.  Connect an antenna to one end and the radio to the other end.  Put the capacitor at, say, half value.  Tune the radio until it comes to a dead spot – no signal at all.  Then note the radio’s frequency and use the formula given in the Hot Iron article to calculate the inductance.

Here’s a nifty Signal Generator circuit which you can modify as desired.

The Dim Lamp Tester (a.k.a. Dim Bulb Tester) is a gadget every builder or restorer of old equipment should have.    Page 28 of Hot Iron #101 also explains and illustrates this device and page 19 of Hot Iron #103 has more details about this item.

And here is another web page about the Dim Bulb Tester, with good photos of the layout as well as a simple schematic.  This one is from “Radio Winkles.”

The wattage of the light bulb to use should be about the same as the wattage of the device under test, or a little more.  If the bulb’s wattage is too small, it will tend to glow a bit even if there is nothing wrong with the device under test.

QRP Power Meter.  How many watts is your device outputting?  G3PCJ has provided an easy-to-build schematic and article about this device.  The schematic and the explanatory text about this device can be found in Hot Iron #3:

VK3YE provides another QRP wattmeter design…very simple.

 

 

 

 

 

 

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