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by bgoated01
852 days ago
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It has apparently been longer since I was a TA for an electronics class in college than I realized. I appear to have lost most of that knowledge. I would love a one-sentence explanation of what each of these circuits you put together are meant to demonstrate, if you're up for it. |
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http://tinyurl.com/27m6usjw rc-filtering a (badly simulated) rc-filtered gpio pin to observe the v-i curve of a diode over the relevant range to measure its temperature
http://tinyurl.com/23u2y4w8 checking an input-protection design sketch for a 500kbps open-drain communications bus to make sure it doesn't degrade the signal too much
http://tinyurl.com/2cf5kgxc adaptor for probing a logic circuit with your cellphone's headphone jack without risk of blowing up your phone or loading down the circuit (though probably just a resistor would be fine for this actually)
http://tinyurl.com/23qvuylw simple linear circuit to supply 5 volts at up to 100 milliamps that won't burn up or drag your power rail down to ground if you short-circuit it, or if you accidentally connect a conflicting voltage source to it
http://tinyurl.com/27agyg4q placing a diode-connected transistor used as a temperature probe in between two rc-filtered gpio pins in order to be able to measure its v-i curve repeatedly at different voltage levels to cancel out possible nonlinearity in the adc you're using to measure it
http://tinyurl.com/2bssxwjq 5-volt linear voltage regulator limited to 150 milliamps with only three transistors and four resistors, eliminating the requirement in the original circuit (from the tektronix 576 curve tracer) for a precisely regulated -12.5 volt rail, but sacrificing some output impedance
http://tinyurl.com/2889h6o8 running several individually switchable devices, including one using a high-precision tl431-based 5-volt regulator, from a 100-milliamp linear regulated current supply over a high-resistance wire, whose unknown temperature-varying voltage drop doesn't affect the current regulator at all, unlike the conventional constant-voltage type of power supply
http://tinyurl.com/2a8by2mq walt jung's gled431, an ultra-low-noise non-temperature-compensated 2.5-volt voltage reference circuit using the forward drop of a lite-on green led as the reference voltage
you could maybe complain a bit that these are a little repetitive, since three of them center around variations on the same standard linear current-source circuit, but it wasn't at all obvious to me how to adapt it to those three cases
overwhelmingly more details in log.md in