Free electronic circuit design and schematic diagram
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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Speed control for dc motor (electric motor) can be implemented using open loop or closed loop. Closed loop controller, also known as servo controller, or a feedback control, gives the best performance since the loop will maintain the actual speed to follow the reference. In simple application, an open loop controller can be enough if the load is constant, such […]
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This small 3 transistors amplifier circuit will be suitable for small battery powered devices, and the circuit is really simple. This tiny power amplifier use same typology as the more complicated version of discrete amplifier in our previous circuit, but with here is in the simplest form. This circuit is a very good start as a DIY amplifier because its […]
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Electric motor has been widely used as motion control, and many type of motor controllers have been designed to provide variable speed drives for the motor. The best controller is the servo controller, where a precise speed control is implemented using a speed sensor in the feedback path. The circuit of the motor controller in this article use a novice […]
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Designing passive crossover network for your speaker system is easy, just like what shown in our previous crossover design article, but now we can design many types of crossover even easier using online crossover design tool. The crossover schematic diagram here is an example with a case of 10 kHz high corner frequency, 1250 Hz low corner frequency, 8 ohm […]
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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 sensitivity to interference are minimized […]
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