Free Circuit Diagram

In the simplest form, current to voltage converter can be implemented as simple as one resistor,  since a voltage is developed when an electrical current flow against a resistance. The problem is that the resistance always affect the current by  decreasing the current flow, and the current to voltage conversion is not accurate. In some [...]

Using LM231/331 chip, we can build a low-cost voltage-to-frequency converter, ideal for analog-to-digital conversion, frequency-to-voltage conversion, long-term integration, linear frequency modulation-demodulation, and many other functions.  When it’s used as voltage-to-frequency converter, the output will be a pulse train with frequency linearly equal to the applied input voltage. For higher level of accuracy against temperature drift, [...]

High voltage current sensing/monitoring can be designed using LTC6101 op-amp. The following current sensing circuit is capable of measuring electrical current in 500 volts system. Here is the schematic diagram of the circuit: Two external Mosfets is added to hold off the voltage, allows the LTC6101 to be connected to a very high [...]

Frequency meter can be used in speed sensor, tachometer, or any measurement of repetitive signals. This frequency to voltage converter (FVC) can be used to turn your analog or digital voltmeter into a tachometer. The circuit’s schematic diagram is shown below. The circuit consist of three blocks. The first block is a squarer, [...]

Using VFC110 chip, we can build a high frequency voltage-to-frequency converter. The features of this chip include the capability of high frequency operation, disable function, and an on-board precision 5V reference. This precision reference can be used to provide reference for offsetting the VFC transfer function, as well as provide transducer or bridge excitation. As [...]

Voltage to frequency is very useful in many situation, such as transmitting temperature measurement using standard voice radio transceiver. This circuit (see the circuit’s schematic diagram) uses only two CA3130 op-amps, but the performance is good enough. The linearity of the voltage-frequency transfer is better than 0.5% and the temperature coefficient is lower [...]