Positive Regulator with PNP Boost

Positive Regulator with PNP Boost
The IC8211 (Programmable Voltage Detectors) provides the voltage reference and regulator amplifier, while Q1 is the series pass transistor. R1 defines the output current of the IC8211, while Cl and C2 provide loop stability and also act to suppress feedthrough of input transients to the  output supply. R2 and R3 determine the output voltage as follows : (more…)

Variable Voltage Regulator based LM117

Variable Voltage Regulator based LM117
The regulator circuit uses an LM117K three-terminal adjustable output positive voltage regulator in a TO-3 can. The variable voltage regulator lets you adjust the output voltage of a fixed DC power supply between 1.2 and 37 VDC, and will supply the output current in excess of 1.5 A. (more…)

Variable Zener Diode

Variable Zener Diode
This circuit acts like a zener diode with a wide range of voltages. The current passing via the voltage divider R1-R2 is substantially greater compared to the transistor base current and is in the region of 8 ma. (more…)

Low Voltage Regulators with Short Circuit Protection

Low Voltage Regulators with Short Circuit Protection
These Low Voltage regulators with short circuit protection can provide 6, 7.5, and 9 V from an automobile battery supply of 13.5 V nominal, however, they will function just as well if connected to a smoothed dc output from a transformer/rectifier circuit. (more…)

Current Source / Regulator

Current Source / Regulator
The Current Source/Regulator circuit powers the load through the regulator's input rather than its output. Since the regulator's output sees constant dummy load R1, it attempts to consume a constant amount of current, regardless of what the  voltage across the actual load really is. Therefore, the regulator's input works as a constant current source for the actual load. (more…)