# Resources [DC Theory Playlist by EEVblog](https://www.youtube.com/playlist?list=PLvOlSehNtuHtVLq2MDPIz82BWMIZcuwhK) ## Voltage vs Power vs Energy ![[Pasted image 20250501115152.png]] ## DC Voltage and Current Source Theory ![[Pasted image 20250502103916.png]] - Thevenin and Norton equivalent circuits - Thevenin equivalent circuit - Essentially a voltage source with a series resistance - Any linear circuit (non linear breaks the laws of physics idk) containing voltage sources, series resistance and current sources can be model as a voltage source with a resistance in series - Thevenin and norton circuits can be modeled as one another Norton left and thevenin equivalent right ![[Pasted image 20250502111526.png]] - Norton equivalent circuits can be modeled as current sources in parallel with a series resistance - All voltage sources have some series resistance. If they didn't (theoretically) we could have infinite current ![[Pasted image 20250502105036.png]] A current source can only produce constant current until the max compliance voltage, which is the thevenin voltage. The compliance voltage is I x Rs. Ohms law. I = V/R or V = I x R or R = V/I ## Resistive Voltage Dividers ![[Pasted image 20250503090449.png]] Vout < Vin Series Resistors ![[Pasted image 20250503090833.png]] Rt = R1 + R2 + Rn + ... Parallel Resistors ![[Pasted image 20250503090844.png]] 2 parallel resistors: Rt2 = R1 x R2 / R1 + R2 More than 2 parallel resistors: Rt = 1 / (1/R1 + 1/R2 + 1/Rn + ...) Rules of thumb If you want to lower voltage output after a resistor by: 10 % put a 10x higher resistor in parallel 1% put a 100x higher resistor in parallel 1/2 use 2 resistors in parallel 1/3 use 3 resistors in parallel If you want to increase voltage output (?) after a resistor by: 10% put a 1/10 resistor in series 1% put a 1/100 resistor in series What exactly are the effects of resistors in series and in parallel to voltage and current? ![[Pasted image 20250503092856.png]] Vout = (R2 / R1 + R2) x Vin General formula: Vout = (Rn / Rt) x Vin ## Current Dividers ![[Pasted image 20250503093331.png]] I1 = (R2 / R1 + R2) * I Only applies to 2 resistors in parallel. For more, need Kirchhoff's Law Why are the resistors in parallel and we're adding them to get the total?