People
This is a very short example. Building a load for a power supply should be a meta or sticky better written than this.
I often power up a just built or worked on power supply on a simple resistive load bank. This can save the circuit that you just built from overvoltage
You need to know how to use ohms law and DC power.
Lets say a G7 go to the spec sheets and find the fil current and voltage
Use Voltage 6.3 VDC and current .2 amps to start
a resistor to sub for the heater would be 6.3/.2 for 31.5 ohms use a 33ohm it is close enought.
Next you know the current and voltage so voltage X current = DC power
6.3VDC X .2amps =1.26watts
33 ohms at 2 watts
or three 100 ohm in parallel at .5watts for 33.3 ohms at 1.5watts.
Now if you underheat the voltage and current will be a little different but this should be close for a load test of the power supply
Simple stuff
Then do the B+. One way, Look at the cathode voltage divide the cathode resistor voltage by the resistor value this should be very close to the plate current. Or you could use the voltage drop across the plate R
Then calculate the capsule voltage divider and pattern resistors total value and then that value current at the rated B+
Add up the currents and calculate the needed resistor value and wattage.
Ripple you will need a scope for.
This is a very short example. Building a load for a power supply should be a meta or sticky better written than this.
I often power up a just built or worked on power supply on a simple resistive load bank. This can save the circuit that you just built from overvoltage
You need to know how to use ohms law and DC power.
Lets say a G7 go to the spec sheets and find the fil current and voltage
Use Voltage 6.3 VDC and current .2 amps to start
a resistor to sub for the heater would be 6.3/.2 for 31.5 ohms use a 33ohm it is close enought.
Next you know the current and voltage so voltage X current = DC power
6.3VDC X .2amps =1.26watts
33 ohms at 2 watts
or three 100 ohm in parallel at .5watts for 33.3 ohms at 1.5watts.
Now if you underheat the voltage and current will be a little different but this should be close for a load test of the power supply
Simple stuff
Then do the B+. One way, Look at the cathode voltage divide the cathode resistor voltage by the resistor value this should be very close to the plate current. Or you could use the voltage drop across the plate R
Then calculate the capsule voltage divider and pattern resistors total value and then that value current at the rated B+
Add up the currents and calculate the needed resistor value and wattage.
Ripple you will need a scope for.