Free electronic circuit design and schematic diagram
The Vc1 increases linearly when the pull-up resistor RA in the monostable circuit is replaced with constant current source, generating a linear ramp. The linear ramp generating circuit and the generated linear ramp waveforms illustration is shown in figures below. Current source is created by PNP transistor Q1 and resistor R1, R2, and Re. Ic= (Vcc-Ve)/Re Ve= Vbe + (R2/(R1+R2))Vcc […]
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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, enter the values of R1, […]
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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 by the R2-C1 circuit which […]
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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 output volume and the 100k […]
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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 shelving frequencies is predicted by […]
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The load inrush current is limited by the TPS2331. The system also protected by TPS2331 from a load fault in its traditional tole as a hot-swap controller. However, the TPS231 must protect the system against a power supply module fault in an OR-ing circuit. The TPS2331 is required by the former role to trip if excessive current flows into the […]
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Below is a 2-station intercom using common 8R mini speakers. The “press-to-talk” switches should have a spring-return so the intercom can never be left ON. Power the speaker from a separate power supply is the secret to preventing instability (motor-boating) with a high gain circuit like this. An extra station (or two extra stations ) can be connected to this […]
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