Averager and Peak Hold/Extender Signal Conditioner

A signal averager circuit can be formed by an amplifier and active signal rectifier, which is implemented using two operational amplifiers in this circuit. The first op-amp is configured as inverting amplifier and the second forms an active half-wave rectifier. The half cycle signal is then filtered by an RC (resistor-capacitor) filter to get the average value. The gain of […]

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Heart Monitor (ECG Sensor Signal Amplifier/Conditioner)

Using the circuit depicted in the schematic diagram below we can monitor the heart pulses of patient. This circuit buffer and amplify the heart pulses, and the amplification bandwidth ranges from DC to 3 kHz. For the core of the isolation, a Burr-Brown BB3656 isolation amplifier integrated circuit (IC) is used in this circuit. With internal transformer inside, this integrated […]

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Supply Voltage Monitor with 555 IC

This is a supply voltage monitor circuit, an indicator to show if the power supply is in good condition. Designed using the IC 555 timer, this circuit will flash the LED1 when the supply voltage surpass preset level.  With flashing indicator, at least there will be two benefits, first, the power consumption will be lower since the indicator doesn’t have […]

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