Variable Voltage Controller

Discussion in 'The Projects Forum' started by alexilla, Jan 24, 2011.

  1. alexilla

    alexilla Thread Starter New Member

    Jan 24, 2011
    I need some suggestions on creating a power supply that is capable of varying voltage from near zero to 120vac at about 3A and is capable of accepting a milliamp signal from a controller IC. I need a very quick response time for partial load to full load voltage. This is for varying the voltage on an electrical resistance heater coil that has to maintain a set airflow temperature through a tube. As the airflow varies from none to high flow, the coil voltage has to continuously adjust to maintain the temperature set point and to avoid damaging the coil when the airflow is minimal. ie... low airflow, low coil voltage; high airflow, high coil voltage. Any help would be greatly appreciated. Thank you.
  2. beenthere

    beenthere Retired Moderator

    Apr 20, 2004
    Missouri, USA (GMT -6)
    The resistance heater will operate on DC as well as AC, and with DC you can use a form of PWM to control the heat. Otherwise, you can use a TRIAC to control current.

    That milliamp level signal will almost certainly need amplification. Can you post the schematic?
  3. wayneh

    wayneh AAC Fanatic!

    Sep 9, 2010
    Roscoe, IL
    That's a unit of measure, not an amount. Do you mean in the hundreds of mA (probably usable without amplification), or single digits (needs amplification)?

    I agree that PWM control of a MOSFET "switch" would be a good option here to control a DC heater, with the PWM being controlled by the controller voltage.

    The old-school approach is a variac under thermostatic control.
Similar Threads
Forum Title Date
The Projects Forum Variable breadboard rail voltage Apr 6, 2015
The Projects Forum Variable Voltage Mar 19, 2015
The Projects Forum Medium to High voltage variable power supply Dec 18, 2014
The Projects Forum Variable Voltage phone charger Sep 12, 2014
The Projects Forum Square Wave with Variable Voltage Nov 29, 2013

Share This Page