Title: PID temperature controller - substitute a MOSFET for an SSR?
Post by: pcbsmoke on March 30, 2016, 05:35:40 am
Post by: pcbsmoke on March 30, 2016, 05:35:40 am
I am working on a project trying to see if it is possible to substitute a MOSFET for an SSR as a means for switching a soldering iron on and off with a PID temperature controller. Please see attached block diagram and partial schematic below:
Edited diagram and the specification - added the LED and resistor Mar 30, 2016 ...
[attachment=0]
I want to know is there a way to use a transistor in the circuit to do the switching? When the SSR signal is "on" (Vin ~8v) it needs to open the connection between A and B and switch the load on. When the SSR signal is "off" (V0) it needs to close the connection between A and B and switch the load off.
I breadboarded the circuit and basically used one of the breadboard leads as a switch between A and B. I used an LED and resistor to simulate the load and another LED and resistor connected to the PID controller to simulate the SSR signal. When the connection between "A" and "B" is closed, the LED simulating the SSR blinks on and off in sync with the PID controller. When the connection between "A" and "B" is open (I pull the lead out of one side) the LED simulating the SSR shuts off and the LED simulating the load lights up.
Test board with soldering iron, PID controller, transformer and breadboard:
[attachment=2]
Closeup of breadboard next to step down converter / voltage regulator for powering the load LED
[attachment=1]
Any help would be appreciated.
Thanks in advance.
Edited diagram and the specification - added the LED and resistor Mar 30, 2016 ...
[attachment=0]
I want to know is there a way to use a transistor in the circuit to do the switching? When the SSR signal is "on" (Vin ~8v) it needs to open the connection between A and B and switch the load on. When the SSR signal is "off" (V0) it needs to close the connection between A and B and switch the load off.
I breadboarded the circuit and basically used one of the breadboard leads as a switch between A and B. I used an LED and resistor to simulate the load and another LED and resistor connected to the PID controller to simulate the SSR signal. When the connection between "A" and "B" is closed, the LED simulating the SSR blinks on and off in sync with the PID controller. When the connection between "A" and "B" is open (I pull the lead out of one side) the LED simulating the SSR shuts off and the LED simulating the load lights up.
Test board with soldering iron, PID controller, transformer and breadboard:
[attachment=2]
Closeup of breadboard next to step down converter / voltage regulator for powering the load LED
[attachment=1]
Any help would be appreciated.
Thanks in advance.