In order to take a high speed photograph one must either have a very fast shutter or light source. We followed the latter course and first examined an commercial flash unit to determine its light profile. This was accomplished by exposing a phototransistor connected in an emitter follower configuration with a relatively low impedance emitter resistor to the flash and viewing the resistor voltage
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with an oscilloscope. Since we did not have a fast digitizer or camera available the observed trace was roughly hand sketched. The figure to the left shows the observed data. The phototransistor circuit appears in the right of the figure and the light curve of the commercial flash unit is shown at the lower left. It can be seen that the pulse length is around 175 µs which is far too long. For example, a 130 m s-1 object (295 mph) will travel 22 mm in that time. We set about to build our own light with a significantly shorter pulse length. Fortunately, a U-shaped xenon flash lamp and companion pulse transformer were available from a local Radio Shack (and still are although the pulse transformer is now a special order item) and there were a few high voltage capacitors in the junk box. A high voltage (several hundred volt) power supply was also laying about which was built for another project at least twenty years ago. A very nice reflector was obtained from a hand-held lantern, drilled out to pass the flash lamp, and attached to a small plastic box with epoxy. The electrical components were mounted free-standing inside the box, a male DB-9 connector was used to connect to the high voltage source, a "short-to-fire" connector was implemented with a female 1/8" phone jack, and a momentary contact switch was utilized as a "push-to-test" button. The following figure shows a collection of views of the home-made strobe flash unit....
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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