Author: Circuitguy

Single Chip Thermocouple 4-20mA Current Loop Transmiter Circuit

Thermocouples give many benefits compared to thermistor/RTD (Resistance Temperature Devices).  Some advantages of thermocouple are their wider temperature range, their reliability, and their consistency over long period of time. In some cases,  thermocouple calibration  is even unnecessary. Thermocouple temperature sensors are widely used in temperature controllers for boilers, oven,  pressurized reactor, even in high temperature furnace. A general purpose temperature […]

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Category: Control and Monitoring, Testing and Measurement Tags: , ,

Passive Crossover Network Design for Hi-Fi Speaker

Crossover network for speaker can improve the quality of the sound, reducing the distortion level caused by excessive signal beyond the speaker’s frequency response. This articles describes how you can design your own crossover networks for your Hi-Fi speaker set. Both first order  and second order passive filter will be explained in this article. First order crossover network will give […]

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Category: Audio Tags:

Transformerless Voltage Booster Circuit: A DC-DC Step-Up Switching Regulator Using Transistors

A DC-to-DC step-up converter is traditionally implemented using transformer, working by converting the DC voltage to AC Voltage, step-up it using transformer, then rectify and filter the transformer’s output to  get a higher DC voltage. Using a switching method, we can step-up a voltage without a transformer. We just need an inductor which is driven by a switching transistor to […]

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Category: Power Supply Tags: ,

5-Band Graphic Equalizer Circuit Using LA3600 Integrated Circuit Chip

Using a special purpose single IC chip LA3600, we can build a graphic equalizer with low components count.  The internal design of the chip uses transistors gyrator circuit, with connections to external capacitors to set the response. This graphic equalizer circuit is suitable for tape-recorders, radio-cassette recorders, car stereos, or home theater sound systems. You need a pair of this […]

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Category: Audio Tags: ,

Small AM Transmitter Circuit: Using Logic Gates!

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 recommended since it need shorter […]

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Category: RF and Video Tags:

Single Transistor Microphone Pre-Amplifier for Both Dynamic and Condenser Type Mics

Condenser microphone and dynamic microphone (moving coil microphone) has different characteristics. For dynamic mics, a biasing current is not needed because the transducer generate the electrical signal. In condenser mics, a bias current is needed to compensate the leakage in the microphone, and because of the pre-amplifier loading that discharge the condenser mic’s electrical charges. The microphone pre-amp described here […]

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Category: Audio Tags:

Active Crossover Circuit: Split The Audio Signal Before Amplification

You might be familiar with passive crossover network installed inside your speaker box, consist of inductors and capacitors. The problem with passive crossover network is that they dissipate the audio power, so it’s not environmentally friendly, contributing a little disaster of global warming.  Moreover, the capacitor and the inductor in the passive crossover network contribute the distortion of the signal […]

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Category: Audio Tags:
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