RANDOM PAGE
SITE SEARCH
LOG
IN
SIGN UP
HELP

Voltage Regulator

This is the AQA version closing after June 2019. Visit the the version for Eduqas instead .

To gain access to revision questions, please sign up and log in.

Voltage Regulator

Higher power circuits such as audio power amplifiers and voltage regulators pass significant currents. Under these conditions, the resistance of thin copper circuit board tracks can become important. To minimise this resistance, the connections to the 0 Volt line should be as close together as physically possible. This is called Single Point Earthing.

Single Point Earthing

Failure to use single point earthing can have the following consequences ...

Parasitic oscillations.
- The circuit oscillates unexpectedly.
- Both low and high frequency oscillations can occur.
Mains Hum.
- 50/60 Hz AC mains supply hum can appear in the output.
- With audio systems this is a low pitched annoying humming noise.
- With DC supplies, the DC may not be as smooth as it could be.

The circuit above is a power supply voltage regulator.

It uses the 7805 chip to provide an accurate 5 Volt output.
The input needs to be about 8 to 15 Volts.
The decoupling capacitors reduce the risk of unexpected oscillations.
With a heat sink, this circuit can supply up to one amp.
Lower current versions of the chip are available too.