1、1/ Capacitors and resistors have parasitic inductance, about 0.4nH for surface mount and 4nH for a leaded component. 2/ If you don"t want a high bandwidth transistor to oscillate place lossy components in at least 2 of the 3 leads. Ferrite beads work well. 3/ When taking DC me
2、asurements in a circuit and they don"t make sense, suspect that something is oscillating. 4/ Opamps will often oscillate when driving capacitive loads. 5/ The base-emitter voltage Vbe of a small signal transistor is about 0.65v and drops about 2mV/deg C. Vbe goes down with inc
3、reasing temp.6/ Multiply 0.13nV by the square root of the ohmic value of a resistor to find the noise in a 1Hz bandwidth. Then multiply by the square root of the BW in Hz gives the total noise voltage. 7/ Johnson noise current goes down with a increase in resistance.8/ The imp
4、edance looking into the emitter of a transistor at room temp is 26Ohm/Ie in mA 9/ All amplifiers are differential in that they are referenced to ground somewhere. 10/ Typical metal film resistor has a temp coef of about 100 ppm/deg C 11/ The input noise voltage of a quiet op a
5、mp is 1nv/sqrt(Hz) but there are plenty available with 20nV/sqrt(Hz). Op amps with bipolar front-ends have lower voltage noise and higher current noise than those with FET front-ends 12/ Using an LC circuit as a power supply filter can actually multiply the power supply noise
6、at the filter"s resonant frequency. Use inductor with low Q to overcome this. 13/ Use comparators for comparing and op amps for amplifying and don"t even think of mixing the two. 14/ Ceramic caps with any other dielectric other than NPO should only be used for bypass applicati
7、ons. 15/ An N-channel enhancement-mode FET needs +ve voltage on the gate-source to conduct form drain-source. 16/ Small signal JFETS work very well as low-leakage diodes by connecting drain & source together in log current-to-voltage converters and low leakage input protection
8、. Small signal bipolars with b-c tied together will also make
