Am new to electronics. The high impedance voltmeter is analog right? How high does the voltmeter reading go? Is it only 9 volts? I see see the Tlo82 Op amp but not the other Op amp in the circuit?
The impedance of a simple analog voltmeter depends upon the sensitivity of the meter movement and the range the meter is set to. For a typical 20,000ohm/volt sensitivity VOM (Volt-Ohm-Milliamp Meter) On the 1v range, the input impedance will be 20,000*1 or 20,000 ohms. On the 100v range, it will be 20,000*100 or 2 megohms. Some really cheap meters could be 1000 ohms/volt. For meters with signal conditioning circuits, like a digital multimeter (DMM) the input impedance is normally a constant value, like 10 megohms irregardless of its range.