Here is the circuit of a Op-Amp based Square Wave Generator. One of the main application of this is in a Simple PWM circuit and Triangle Opamp Oscillator. The Slope of the Triangle wave is compared with a DC Level to derive a pulse width or On-Time proportional to a Voltage.
This On-Time proportional to voltage [...]
Archive of entries posted on October 2008
Square and Triangle Opamp Oscillator
2N2646 based Voltage controlled SCR Pulser
A Center tap 50Hz Step Down Transformer with two diodes is used to get a train of Positive Sine Pulses at 100Hz which is applied to Q6 base via R51. 2N2646 is a unijunction transistor(UJT) in a TO-18 metal package. The control voltage or voltage proportional to error is fed to R56-Q3, The UJT drives [...]
Two Setpoint Temperature Controller
A Two Point Process Controller or Temperature Controller would look like this. When a High-Low Alarm Protection for uC based Controller was needed the same was modified and used.
Sometimes uC based instruments just forget and that can be costly, the watchdog timer has solved this problem. In Industrial Process Control we cannot take any chances, [...]
Temperature Controller for Cooling Chamber
This is part of an user manual i used to give for cooling controllers – app007.pdf
The Logic of cooling in temperature control is inverted, Activating the relay powers a compressor which cools the system. A small modification at the output stage, makes any heating controller into a cooling controller. It can also be done with [...]
