One classic set you’ll see in most гvintage mystery movies is an interrogation room with a “two-way” mirror in one wall. This cool gadget lets the witnesses see the suspects from another room while the suspects can see only ...
A recent Design Idea, “Three discretes suffice to interface PWM to switching regulators”( Reference 1 ), demonstrated one way to use PWM to control the output of a typical switching voltage regulator. There were some discussions in the ...
In Part 1 of this Design Idea [ 1 ], we saw how a standard electret microphone capsule can be persuaded to detect infrasonic signals down to a fraction of a Hertz by adding some fairly simple equalization. In this second and concluding part, we ...
Electrets aren’t only used as audio pickups. For decades, they have been employed in security systems to detect unexpected changes of air pressure within rooms, while more recently they can be found in vapes as suck-sensors (or, more ...
In April 2012, EDN published a circuit by John Fattaruso ( Ref. 1 ) that lets you quickly measure the drain-source saturation current and the pinch-off voltage of both an N-JFET and a P-JFET. The pinch-off voltage (V P ) is measured by inserting a ...
Figure 1’s circuit is not as fast as some other circuits, but its 2.5 MHz output settles from a full-scale input step in only 3 us. This makes the circuit a good candidate for FM applications or any area where fast response to input movement ...
Generating analog sawtooth waveforms (linear ramp followed by a quick reset to zero) from digital timing signals is a common function. It usually requires a negative supply as sketched in Figure 1, where Negative current through R1 ramps up ...
If you have a load with a variable or poorly specified resistance and want to regulate the power applied to it (a heater for example), merely controlling the voltage or current will not work, as in both cases the power P = I 2 R = V 2 /R depends on ...
Figure 1 gives a simple circuit for the PUSH ON, PUSH OFF function with only a few inexpensive components. In this design, the output is connected to the input of the gadget when you press the push button (PB) once. For the next push, the output is ...