Archive for the ‘RF and Video’ Category
Field Strength Meter
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 …[Read More]
AM Radio Receiver Circuit Using TDA 1072AT IC
TDA 1072AT is a special purpose integrated circuit for AM radio receiver from Philips Semiconductors. The integrated circuit is designed for mains-fed home receivers and car radios. The voltage-controlled oscillator provides signals with extremely low distortion and high spectral purity over the whole frequency range even when tuning with variable capacitance diodes. RF radiation and …[Read More]
For you who has failed to build radio transmitters, this circuit worth a try. This circuit uses 74HC14 hex Schmidt trigger as the oscillator, and you can choose to use capacitor for low cost goal or quartz crystal for better stability. For quartz crystal, you can choose any frequency between 00.7-1.6MHz, but around 1.6MHz is …[Read More]
Single Transistor Wireless Microphone (FM Transmitter)
This wireless microphone circuit uses only a single transistor, with few additional passive components. This FM transmitter is very compact and need only a single cell 1.5Volt battery, even works on 1.2V rechargeable battery. Here is the schematic diagram of the circuit: The transmission range could be between 30-50m radius in open air, and practically …[Read More]
Two Transistors Wireless Microphone (FM Transmitter)
Please be warned if operating this circuit might violate the regulation of your country, because this FM transmitter circuit radiate strong radio frequency to the environment. This wireless microphone is very sensitive, pick up every sound in the 20m radius, and transmit the radio signal up to 2 kilometers in open air. Here is the …[Read More]
Single Chip Stereo FM Transmitter Circuit: A Very Compact Design
ROHM (www.rohm.com) is originally a resistor producer company, but finally expand their business and produce monolithic IC, and this one used in our circuit is the example. The internal structure of this FM transmitter integrated circuit consist of stereo modulator that creates a stereo composite signal, an FM modulator that modulate a carrier frequency with …[Read More]
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