Powering LED from Single AA Cell
The benefit of LED is longer lifetime than incandescent lamp, and even higher efficiency in latest LED technology. LED is also very compact, but unfortunately it needs higher voltage to operate. A single cell battery (1.5v) or rechargeable cell (1.2V) cannot be used to power LED directly. We have to use a DC-to-DC step-up converter …[Read More]
Bandpass Filter’s Gyrator Frequency Calculator
Gyrators are synthetic inductors, which are often used to form bandpass filters. As shown in the two examples here, the active buffering device can be a transistor or op-amp. This type of bandpass filter is commonly used in graphic equalizers and other frequency control circuits such as tone controls. In the gyrator frequency calculator here, …[Read More]
Typical LED indicator consist of resistor (R2) and LED, connected in series with a switch. When the switch is closing or opening, a glitch noise may occur at the supply line. To avoid this noise, R2 and C1 are added to the indicator circuit and value of R1 is adjusted. Very slightly delay is provided …[Read More]
Passive Treble Control for Guitar Pedal
The R1/C1 network makes a low pass filter when the wiper is at the grounded end of the tone pot, and there is a treble cut. The C1 cap bypasses R2 when the wiper is adjusted so that it is at the top end of the pot and it creates a treble boost. The 100k …[Read More]
Passive Baxandall Tone Control (2 Band Equalizer)
Variation of the famous Baxandall circuit is shown in the passive circuit in figure 1. Smoothly increasing +- 6 dB/octave slope of boost or cut is the feature of this circuit. Although the “shelves” are outside the audible range with these component values, the bass and treble filters have a shelving response. The threshold and …[Read More]
Digitally Controlled Dual Polarity Amplifier
This schematic diagram below shows a Digitally Controlled Dual Polarity Amplifier circuit. The circuit (a) can give a means of amplifying a signal either in non inverting and inverting mode. When S2 is off and S1 is on, the noninverting input of the op amp is fed by the signal. The circuit behaves as a …[Read More]
Wheatston Bridge PWM Signal Conditioner
This is a schematic diagram of a Wheatston Bridge PWM Signal Conditioner circuit. This circuit uses the MAX1452 signal conditioner. A ratiometric compensated output for the Wheatstone Bridge is generated by the MAX1452. Then the output of the Wheatston bridge is converted to a PWM output. the PWM-output duty cycle changes accordingly, as the MAX1452 …[Read More]
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