Free electronic circuit design and schematic diagram
For RF (radio frequency) transmitter experiment, watt meter is useful for optimizing the transmitter circuit. A simple RF watt meter circuit is shown in the schematic diagram below. Because circuit is not frequency sensitive, calibration is accurate on all HF bands. The sensitivity is affected by meter movement, number of turns in primary coil, and resistive voltage driver. Pots can […]
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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 circuit is another radio frequency (rf) field strength meter, similar with our previous field strength meter circuit, but with lower supply voltage (only a single cell 1.5V battery). Here is the schematic diagram of this rf strength meter circuit: To use, turn on transmitter and meter; adjust C1 for peak reading. Turn off transmitter and adjust R1 for a […]
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This instrument is very useful for radio frequency (rf) engineer and hobbyist, especially when he/she has to adjust the final rf transmission. Setting up an antenna impedance matcher is one of the example. Here is the schematic diagram of this rf meter circuit: The circuit use only one transistor (MPSA18) as the active component. The signal strength meter display uses […]
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