Diaphragm (optics) curved blades improve the roundness of the iris opening. In a photograph, the number of blades that the iris diaphragm has can be guessed by counting the number of diffraction spikes converging from a light source or bright reflection. For an odd number of blades, there are twice as many spikes as there are blades. In case of an even number of blades, the two spikes per blade will overlap each other, so the number of spikes visible will be the number of blades in the diaphragm used. This is most apparent in pictures taken in the dark with small
Electromagnetic diaphragm Electromagnetic diaphragm An electromagnetic diaphragm is a form of capacitive sensor used on an electronic stethoscope. The diaphragm is coated with a conductive material. A conductive plate is positioned behind and parallel to the diaphragm, so that the two conductive elements form a capacitor. Capacitance is a function of plate area, dielectric properties of the space between the conductors, and the distance between the conductors. It is this latter parameter which is modulated by vibration such that the capacitance varies with the distance between the electromagnetic diaphragm and the plate, forming an acoustic sensor. The electromagnetic diaphragm is a form