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High CMRR Instrumentation Amplifier (Schematic and Layout) design for biomedical applications

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Instrumentation amplifiers are intended to be used whenever acquisition of a useful signal is difficult. IA’s must have extremely high input impedances because source impedances may be high and/or unbalanced. bias and offset currents are low and relatively stable so that the source impedance need not be constant. Balanced differential inputs are provided so that the signal source may be referenced to any reasonable level independent of the IA output load reference. Common mode rejection, a measure of input balance, is very high so that noise pickup and ground drops, characteristic of remote sensor applications, are minimized.Care is taken to provide high, well characterized stability of critical parameters under varying conditions, such as changing temperatures and supply voltages. Finally, all components that are critical to the performance of the IA are internal to the device. The precision of an IA is provided at the expense of flexibility. By committing to the one specific task of ...
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Two Speed Contactor DC Motor Controller Circuit

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The simplest of all motor controllers (besides a beeline on/off switch) is the contactor controller. I advised this contactor ambassador for use in my electric scooter project. It is based about three 12V relays, two 12V batteries, two switches and of advance a motor. Having no silicon to “fry”, it is absolutely reliable and robust. A contactor ambassador works by rearranging the two (or more) accumulation batteries amid alternation and parallel. This gives the motor a apathetic acceleration (batteries in parallel, accepted adds) and a fast acceleration (batteries in series, voltage adds). This assures that both batteries are absolved equally. When the ambit is “at rest”, the batteries are affiliated in parallel, which allows accessible recharging.

Notes
1. S1 closes K3 and appropriately causes M1 to operate. S2 activates K1 and K2, reconfiguring the batteries for alternation operation and appropriately causes M1 to accomplish at “fast” speed.
2. B1 and B2 should be called based on the accepted requirements of M1. Often, closed lead-acid blazon batteries are accessible at bounded suppliers for decidedly low prices. These batteries are ideal for things such as scooters, go-karts, etc.
3. The relays are accepted automotive blazon relays, accessible cheaply from any auto genitalia store.
4. Your motor will depend on your requirements. 12V motors will commonly run accomplished at 24V, and carnality versa.
5. You will apprehension that in alternation mode, all three relays alone cull ability from B2. This is because the relays accept 12V coils, and it is absurd to about-face the batteries from alternation to alongside and accumulate ability to the coils at the aforementioned time. This does, however, beggarly that B2 is absolved slighty afore B1. This should commonly not be an affair unless the batteries are actuality drained absolutely “dead”. Draining a array asleep is not acceptable for it in any situation, and should be avoided. If you wish, you can use a baby 12V array to run the relays separately.
6. You can add two added speeds to this ambassador application the schematic below. It connects at credibility A and B apparent aloft on the ambassador schematic.

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