Filter, audio, and RF-communications testing often require a random noise source. Figure 1’s circuit provides an RMS-amplitude regulated noise source with selectable bandwidth. RMS output is 300 mV with a 1 kHz to 5 MHz bandwidth, selectable ...
Figure 1 is a “charge pump” type V/F converter specifically designed to run from a 3.3 V rail. A 0 V to 2 V input produces a corresponding 0 kHz to 3 kHz output with linearity inside 0.05%. To understand how the circuit works assume ...
This article describes an active load circuit that can be used to simulate a battery in any state of charge. The battery simulator provides a constant-voltage load for a battery-charging circuit, independent of applied charging current. The ...
It is often desirable to determine a battery’s internal resistance to evaluate its condition or suitability for an application. Accurate battery resistance determination is complicated by inherent capacitive terms which corrupt results taken ...
Self-heated thermal airflow sensors are simple, cheap, rugged, and sensitive. However, they exhibit an airspeed to sensor temperature response ( King’s Law ) that is very nonlinear, as shown in Figure 1. Figure 1. The TO-92 junction ...
I was reminded recently of a tester I designed years ago. At the time, I wanted to build “The Ultimate Continuity Tester,” and I established a wish list of all the features I required: A “real continuity” tester. Too many ...
Low-power, low-cost ceramic piezoelectric rate gyros are available, but they lack the low-temperature-coefficient characteristics of their quartz counterparts. However, you can use a servo amplifier to remove the dc level shift due to ...
Figure 1’s circuit achieves a wider dynamic range and higher output frequency than any commercially available voltage to frequency (V-F) converter. Its 100 MHz fullscale output (10% overrange to 110 MHz is provided) is at least ten times ...
No currently available V-F converter will accept bipolar (AC) inputs. This feature is desirable in power line monitoring and other applications. Figure 1’s V-F converter accepts 10 V inputs, producing a 0 kHz to 10 kHz output. Linearity is ...
The circuit in this Design Idea anticipates, or jumps instantly to, the final voltage of an input-signal change. It relies on the fact that the intended input signal changes exponentially with a known time constant. This circuit was adapted from a ...