Free electronic circuit design and schematic diagram
Using LM134 and LM10 integrated circuits, we can build a thermometer which has -55 to 150°C sensing range. The ideal meter for this circuit is a 0-200uA digital ampere meter, which can show both positive and negative polarity. This will make the circuit suitable for indicating temperatures below 0°C. LM134 is basically a current source with very accurate and consistent […]
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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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Temperature measurement (sensing) and monitoring will be economical and straightforward if we apply the input of TC9400 V/F converter with a voltage from output of a probe, such as shown in diagram below. The V/F output is simply counted to display the temperature. The TC9400 can be used to modulate an RF transmitter for a long distance data transmission. The […]
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This is a 230VAC Temperature Fan Control circuit. This circuit is used for 230Vac operation. The R9 can be changed to 15K 2W, if the AC operation is 115V. This circuit uses the principle of Wheatstone bridge. The Wheatstone bridge is made from R3-R4 and R1-P1. P1-R1 produce a temperature-sensitive “variable” voltage and a fixed two-thirds-supply “reference” voltage is produced […]
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Usually, semiconductor laser diodes are operated from current drives. Unfortunately, The output power is strongly dependent on the device temperature – a rise of 15° causes a fall in optical power of (typically) 17% for a given current. Using a feedback loop and monitor the output beam intensity using photodiode is one method to stabilizing the operating condition. Not an […]
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This schematic diagram is about IL300XC Isolation Amplifier circuit for TMP01 Temperature Sensor. This circuit is used in an environment that needs to be electrically isolated from the central processing area. This circuit uses an 8-pin optoisolator (IL300XC). IL300XC was chosen because it can operate across a 5,000V. To drive the LED connected between Pin 2 and Pin 1, this […]
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