Free electronic circuit design and schematic diagram
Phase-locked loop is very common in telecommunication, control, and other electronic application. PLL can be used to demodulate FM signal, produce a stable clock signal, or to recover a synchronization signal from noise. Many single chip integrated circuits (IC) are produced for this PLL system, and LM359 is one of them. This PLL is capable to operate up to 5MHz, […]
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This is a Shunt Series Pair Wideband Amplifier circuit. This circuit has four feedback loops, they are two emitters feedback, shunt-shunt feedback and an AC feedback loop(series-shunt). This is a very stable circuit and can be used for wideband amplifiers and low gain. This circuit requires +12 supply that restrict the “headroom” of the second resistor. The emitter of the […]
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This is Complementary Pair Vertical Deflection Pre-Amplifier circuit. This circuit is modification circuit of Vertical Deflection Pre-Amplifier for 100MHz scope. This circuit remove few resistor-capacitor combination from the original circuit. That components can be removed because they tweaked the response of the amplifier at high frequencies, so no problem. The second two transistors receive +2V from the two 1N4733 5.1V […]
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Field strength meter is a “must have” equipment if you’re dealing with radio transmitter electronics. Here is one example of this kind of circuit that works for 2.4 GHz band: An optional amplifier can be inserted after the rectification, so it can be used to boost small signal. This circuit works only for short distance transmitter since the signal must […]
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The strength of a radiated signal from a transmitter is measured by this circuit. It is commonly used by model airplane builders to check whether their transmitter are really transmitting the radio signal. One can quickly determine whether the problem lies on the transmitter or the receiver module using this FS meter. The only active element in this circuit is […]
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This is Attenuator Pads circuit. This circuit can be used when testing wireless network links to help simulate real life signal loss. This circuit can handle DC – 18 GHz, 2 watts of power, and have built in SMA connectors. The attenuator pads can be combined to increase the overall attenuation. a long length of high-loss cable, such as RG-174 […]
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This is a Cable Reflection Tester circuit. This circuit can be used to check coax cable runs for shorts or even impedance mismatches. This circuit will send a pulse down the circuit, then the return signal can be checked on an oscilloscope. The distance can be determined by using this equation:distance = time x speed equations. Here is the schematic […]
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