The power transformer has three secondaries: 720V at 120mA center-tapped for the plate and screen supplies, 6. 3V at 3. 5A for the tube filament and bias power supply, and 5V at 3A (not used). Since the 5V secondary is not used, a little more current than 120mA can safely be drawn from the high voltage secondary. The high voltage secondary feeds a c
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onventional full wave bridge rectifier to convert the AC to unfiltered DC, which is then fed to the plate power supply filter. Since the the PIV rating of one diode is not enough, two must be used in series, so the four diodes D1 through D4 are actually two 1N4007 diodes in series. For the purposes of the plate supply, the transformer center tap is not used. However, the center tap is used for the screen supply. The output from the plate rectifier is direct current (DC) but with a large alternating current (AC) component superimposed. The output from the rectifier in fed to a choke input filter. The filter choke allows the DC component to flow through, while offering a very high impedance to the AC component. The filter capacitors are essentially an open circuit to the DC, but they effectively short circuit the AC component to ground. The result is that little of the AC component reaches the output. Since the capacitors have a maximum rating of 450V, two are used in series to form a 900V 50uf capacitor. Two 40k, 10W bleeder resistors in parallel with each of the capacitors serve several important functions: (a) They bleed off the charge on the filter capacitors when the unit is shut off, preventing the possibility of a dangerous electric shock that could occur even though the unit were turned off and unplugged. (b) They provide a minimum load on the power supply to prevent the output voltage from soaring during standby...
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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