Free electronic circuit design and schematic diagram
Using LM10 amplifier and voltage reference, a light intensity meter featured with five decades dynamic range (which is suitable for photographic application) can be built. Please note that the linear to log conversion is not temperature compensated, and can make 40% error (a half stop in photography) at the worst point of conversion slope at ±18°C temperature drift. It should […]
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The schematic diagram below show signal conditioning circuit for remote current loop temperature transmitter. This thermocouple temperature transmitter is loop powered, means it doesn’t need its own power supply since the supply is provided by the current loop receiver. Thermocouple is basically a junction of two different metallic material that measures the temperature difference. This thermocouple signal conditioner circuit is […]
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In furnace operation, it is necessary to make sure that the fuel or gas is ignited properly by detecting the flame. If there’s no flame detected, the situation can be dangerous if the furnace is flooded with explosive gas, so the fuel/gas supply valve should be closed automatically to avoid catastrophic disaster. A thermocouple can be use to detect flame, […]
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This is a over/under voltage monitor circuit. This circuit is used to monitor Any potential from 1 to 15 V. If there is a undesirable variation was occurs, two lamps will flash. The voltage differential fro lamp turn off and turn off is about 0.2V at any setting. Low and high set points are independent of each other. The type […]
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Standing wave ratio(SWR) is a ratio of amplitude of partial standing wave at maximum to amplitude at minimum. Using a Simple Swr Bridge circuit, a SWR can be measured. This circuit give a balanced VSWR meter perfectly, so adjustment is not required. This circuit can be made from a coupler which formed by a 6.5-inch piece of RG-58A/U coax. Here […]
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This is a Frequency Difference Measurement circuit. This circuit consist of two TC9400 that is configured in the F/V mode. So, the TC9400 will convert both frequencies into proportional analog voltage(V1 and V2). This circuit also uses unity gain inverter to invert V2. After that, this circuit will add the V1 and -V2 using the summing op-amp. That operation will […]
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Below is two single ended circuits which connected back to back give differential input. This circuit is not only has differential input feature, but also high impedance, much higher compared with the analog ammeter without this circuit. Here is the schematic diagram of the circuit: [Circuit’s schematic diagram source: seekic.com]
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