# How to measure voltage and current in this given scheme?

#### Dovydas Jančauskas

Joined May 7, 2019
1
Hey everyone,

I'm beginner with a little bit of knowledge. So I have this scheme:

I have multimeter and I want to measure voltage and current of this scheme. So to be more specified, is it possible to measure input and output voltages and currents with multimeter? Could someone mark points where in this scheme these parameters could be measured? Also, is there any possibility to measure voltage from each component? Or to be more clear, what can be measured with multimeter in this scheme and where (at which points/wires)?

#### drc_567

Joined Dec 29, 2008
983
What seems to be the problem?
Cursory examination of the KA2284 datasheet suggests that R1 should be in the 47 Ω range.
Using 1kΩ for R1 may not allow sufficient current for the leds to light up.

#### crutschow

Joined Mar 14, 2008
26,072
Voltage can be measured anywhere on the circuit by just touching the two probes at the desired nodes (typically one probe to ground/common).

To measure current you need to physically remove the node connection and put the meter in series with the node.
If there's a resistor in series with the current you want to measure, the you can measure the voltage across the resistor and calculate the current from Ohm's law ( I = V/R).

Obviously it's generally a lot easier to measure voltage than current.

#### Dodgydave

Joined Jun 22, 2012
9,876
Just measure the current in series with the Vcc supply as normal, the as the Audio is increased and the LEDs start lighting up the total current will be displayed..