Free Simple Circuit Diagram
This is a Wien-bridge sine-wave oscillator circuit. This circuit uses negative-feedback stabilization to make sure the gain won’t go higher than unity to prevent signal distortion. The D2 and D1 will conduct when Negative peaks in excess of -8.5 V. That action will charges C4. The amplifier gain is determined by the biased Q1 that is charged by C4. Offset […]
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The schematic diagram below shows a variable 0-180 degree phase shifter circuit. This circuit can provide phase shifted output (compared with the input) between 0 and 180 degrees for frequencies up to 3MHz with same amplitude (unity gain or gain=1.) This circuit uses inexpensive NPN transistor, 2N3904, but almost any small signal transistor type can be used. Using R5 and […]
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Using a FET and two additional transistors (cascaded to improve the gain), a 5V FET voltage regulator can be formed. The additional Tr2 and Tr3 transistors will improve the output current handling and decrease the output impedance. The output voltage deviate only 0.1V for load current change as high as 60 mA which is caused by load resistance changes that […]
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This is a circuit of 90-125 MHz Crystal which is very useful for VHF/UHF converters. This circuit provide 5 to 15 mW output. High-quality fifth- or seventh-over-tone crystal type can be used in this circuit. Undesired oscillation never reach above 500 MHz because of Ferrite bead FB. Using regulated power supply and allowing crystal to operate at its natural series-resonant […]
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