Free electronic circuit design and schematic diagram
This circuit is a simple crystal oscillator that can be operated in overtone mode. Overtone mode permit the operation at higher frequency than specified by the crystal. The circuit uses a grounded base amplifier configuration, and place the crystal as a series resonator. The transistor Q1 is biased in the active region as an amplifier. L1C1 is a resonant circuit […]
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Sine wave oscillator can be implemented using Wien-Bridge oscillator like in our previous sine wave oscillator circuit, but now we present another method of generating sine wave signal. Using phase shifter, we can build a simple sine wave generator, as shown in the schematic diagram below: Sine wave oscillator using phase shifter has lower distortion than Wien-Bridge oscillator, coupled with […]
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The LM4610 uses DC signal to control the tone (bass/treble), volume, and balance circuit. The advantages of using DC control is that you can use a mono potentiometer to control both channel, even you can use a DC signal generated from a DAC, so you can control the sound using microcontroller or microprocessor. This circuit can applied for car radio, […]
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Using MAX232 integrated circuit, you can build a TTL-to-RS232 level converter that totally comply with RS232 electrical specification. The IC generate the higher positive and negative voltage (+10 and -10 Volts) from TTL power supply (5V DC) using switched capacitor. The switching circuitry is provided inside the chip, so you need only few caps for external components. Here is the […]
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A LT1637 is advertised as 1.1MHz, 0.4V/us Over-The-Top Micropower, Rail-To-Rail Input and Output Op Amp. This features are suitable for current sensing application since input voltages are right at the upper rail. The circuit show current sensing of 5V supply system, but monitoring up to 44V application can be done by this circuit (the maximum supply voltage of the op-amp). […]
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Incandescent lamp has been used to reduce harmonic distortion in sine oscillator circuit. The nonlinear resistance characteristic of the lamp filament help the circuit to shape the signal to approximate the ideal sine wave. Here is the classic Wien-bridge oscillator circuit using the incandescent lamp: You can change the frequency of the oscillator by modifying the R1 (and R2), or […]
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LM56 is a monolithic thermostat designed for simple temperature control. The chip has two programmable threshold that can be used to drive a fan and or alarm. Here is the schematic diagram of the fan control circuit: The circuit will turn on the fan when the temperature rise above 50 Celsius degree, and this threshold is set by the voltage […]
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