Sonda Diferencial

This project is a differential probe for oscilloscope featuring 2 MHz of bandwidth in practical tests with 10x or 100x attenuation, selectable with the SW1 switch. The input impedance is 8 MΩ and can be used for differential voltages up to 450 V when powered by a 9 V battery.

Switch SW2 is used to turn the probe on/off. When turned on, LED2 (ON) will be lit, and LED1 (LOW Bat.) will light when the battery is insufficiently charged (8V). To adjust the voltage at which LED1 will light, swap resistors R30/R32.

P1 is used for Common Mode Rejection Ratio (CMRR) adjustment, and P2 is used for offset adjustment. Capacitors C11 and C12 act on the probe input frequency compensation adjustments.