National 5; Practical electrical and electronic circuits Calculating the value of the series resistor. Measurement and analysis of current and voltage in simple circuits allows us to formulate ...

What are the standard electrical circuit symbols? ... A resistor restricts or limits the flow of electrical current. A fixed resistor has a resistance that does not change. Variable resistor.

Calculating the appropriate resistor values for a photocoupler isn’t complicated, but some basic min/max considerations must be acknowledged in when doing the analysis.