Page 34 - Build Your Own Transistor Radios a Hobbyists Guide to High-Performance and Low-Powered Radio Circuits

FIGURE 2-4 Capacitance meter.

The capacitance meter in the figure is measuring a O.018-IJF capacitor as 0.01744
IJF. Note that it also will measure frequency (hertz or Hz). This particular EXTECH
model measures up to 200 kHz. The company's newer unit, however, the EXTECH
MN26T, will measure frequencies up to 10 MHz, which is suitable for measuring the
frequency of oscillator circuits used in radio projects.

Oscilloscopes

An oscilloscope is a voltage-measuring device that allows one to view voltages as a
function of time. This instrument is useful in .measuring signals from oscillators,
amplifiers, and tuned RF circuits, as well as the AM signal.
But an oscilloscope is not reailly required for the projects in this book. However,
having an oscilloscope allows the hobbyist to troubleshoot faster and understand
radio and electronics better. The waveforms probed at particular parts of the radio

reveal what is happening. A one-channel 10-MHz oscilloscope is a minimum
requirement. Either an analog or a digital oscilloscope will suffice for the radio
projects.
And often one can pick up a good used oscilloscope at an auction or on the
Internet. But beware of the sellers and make sure that there is a good return policy

if the oscilloscope is defective. Figure 2-5 is an example of a four-channel 200-MHz
analog oscilloscope.

FIGURE 2-5 Oscilloscope.