Category «Testing and Measurement»

LT1016 – LS74121 Voltage Controlled Pulse Width Generator/ Monostable Multivibrator

Monostable multivibrator poduces a fixed pulse width when receiving a trigger signal on its input. The pulse width of the output is fixed regardless of the input pulse duration/width. In practical application, the width of the output pulse is determined by choosing the right components values for certain application. With this circuit schematic diagram, we …

Low-Drift High-Impedance JFET DC Voltmeter

The voltmeter shown in the schematic diagram below has very high impedance. The range selector uses conventional voltage divider resistors, but since the following pre amplifier uses JFET, the divider can be designed using very high resistance series resistors. This DC voltmeter circuit also featured with low drift. This circuit uses a pair JFETs, which …

Audible Logic Probe/Indicator

Logic indicator circuit / logic probe is used to identify logic level at any point of logic circuitry. The indicator can be visual (using LED, LCD, of 7 Segments) or auditory (using beeper or speaker). This circuit has a audible indicator, with the help of  a loudspeaker to produce indication tone.  Using the opamp,U1, as …

30-Khz Bandwidth High Linearity Opto-Isolated Amplifier

Using optocoupler to directly transfer a linear (analog) voltage would produce  a large unpredictable linearity error, which is also sensitive to temperature changes. By using frequency modulation, the total system’s linearity will  depend only on the linearity of the V/F and F/V converter, which is fortunately cancel each other if we use similar devices with …