Matt circuit

This application is a low power hall sensor amplifier based on LT6011 , Linear Technology's dual operational amplifier fits 25uV input precision micropower operation and wide 2.7V to 36V supply range. HW-108A is the hall element in the application. At 1V DC bias, it consumes about 2.5 mA with a sensitivity of 4mV/mT. Reducing the bias voltage reduces the power consumption but it also reduces the sensitivity. At this point, to lower the power consumption, micropower amplification takes an important role. Circuit operation is as follows. The LT1790 micropower reference gives a fixed output of 1.25V. The voltage divider circuitry made up of 7.87kΩ  and 100kΩ resistors reduces the voltage and the voltage across the 7.87kΩ becomes 0.09V. LT1782 acts as a buffer. So when this 0.09V is applied as bias voltage across the hall sensor bridge, the current is only 0,23mA. This is about 1/10 of the original value. This means that your batteries will last 10 times longer. On the other hand t...

This circuit was developed to power an AVR microcontroller from a 12 V lead-acid battery. The regulator itself draws only 14 µA. Of course, there are dedicated ICs, for example from Linear Technology or Maxim, which can be used, but these can be very hard to get hold of and are frequently only available in SMD packages these days. These difficulties are simply and quickly avoided using this discrete circuit. Micropower Voltage Regulator Circuit diagram : The series regulator component is the widely-available type BS170 FET. When power is applied it is driven on via R1. When the output voltage reaches 5.1 V, T2 starts to conduct and limits any further rise in the output voltage by pulling down the voltage on the gate of T1. The output voltage can be calculated as follows: UOUT = (ULED + UBE) × (R4 + R2) / R4 where we can set ULED at 1.6 V and UBE at 0.5 V. The temperature coefficients of ULED and UBE can also be incorporated into the formula. The circuit is so simple that of course som...