Free electronic circuit design and schematic diagram
Microphone pre-amp is a very simple circuit, most all low noise op-amp will be sufficient for this circuit (TL071, TL082, OPA371, NE5534, etc). This circuit will be suitable for dynamic microphone, electret microphone (or a condenser microphone with active circuit inside). A condenser microphone (without voltage bias source) won’t work for this circuit. If you want to use it, you […]
Read more
Another example of frequency-to-voltage converter application similar with RPM/Speed Indication is motor speed control. Here the converter is used to measure the actual speed which will be fed back to keep the actual speed stabilized according to a reference. Here is the block diagram of this control system: If the speed is to high, the output of the F/V converter […]
Read more
One example of frequency-to-voltage converter application is RPM/Speed indication, converting pulse signal from speed sensor into a linear voltage to drive analog meter. Here is the block diagram of such speed indication system: Since they measure the number of events per time period, flow rates and revolutions per second are nothing more than frequency signals. This flow and revolution will […]
Read more
A circuit which will divide one analog signal by another is one of the most difficult circuits to build. TC9400 voltage-to-frequency converter make it easy to build such circuit. Here is the block diagram of the system: Two voltage-to-frequency (V/F) converters can do such division with ease. While the denominator forms the time base, the numerator is counted directly as […]
Read more
This is a TC9400 Frequency-to-Voltage Converter circuit. Beside used as voltage to frequency converter, the TC9400 can also used as Frequency-to-Voltage Converter. The TC9400 will convert the input frequency waveform to output voltage linearly. This circuit has a threshold detector’s input that is used to detect each zero. The zero will cause a precise amount of charge(q=Cref Vref) to be […]
Read more
This is a TC9400 10Hz to 10kHz Voltage-to-Frequency Converter circuit. This ciruit uses TC9400 to convert voltage to frequency. The TC9400 uses charge balancing principal. This circuit uses input resistor to convert the input voltage to input current. Then the capacitor will change the current into charge which will decrease the Op amp output voltage linearly. This circuit also featured […]
Read more
This is a Mini MW (Medium Wave) Transmitter circuit. This circuit consist of combination of transistors SA103 and SA101. Those transistors is used as oscillator and modulation signal amplifier. Here is the schematic diagram of the circuit: The transistor is of germanium type, but I think you can replace it with silicon type from the high frequency one. The inductors […]
Read more