Archive for the ‘Basic Function Circuits’ Category
SCR Basic Operation
The diagram below shows us a simple block construction of an SCR (upper left) and its schematic diagram (upper right). The lower diagram shows us the operation of a PNPN device can best visualized as a specially coupled pair of transistor. When a proper gate signal is applied to the base of the NPN transistor, …[Read More]
OP90 Single Op Amp Full-Wave Rectifier
A full-wave rectifier circuit that provides the absolute value of input signals up to ±2.5 V even though operated from a single 5 V supply is shown in the schematic diagram below. The amplifier acts as a unity-gain inverter for negative inputs. The op amp output is forced by positive signal …
We can use tone/frequency detector (decoder) to detect the presence of a signal with a certain tone. The output of the circuit will be active if the signal is the same tone with the tone of a series of internal oscillator. LM567 is one of decoder that we can use. The LM567 and LM567C are …[Read More]
555 IC Linear Ramp (Sawtooth) Generator/Oscillator
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= …[Read More]
555 IC PWM Controller: Grounded and Ungrounded Load
While keeping the oscillator frequency relatively stable, this 555 based PWM controller features almost 0% to 100% pulse width regulation using the 100k variable resistor. To give a frequency range from about 170Hz to 200Hz , the frequency is dependent on the 100k pot and 100n. You can see the charging and discharging of the …[Read More]
Anti-Log Converter
Anti-log or exponential generation is simply a matter of rearranging the logarithmic circuitry. The circuit diagram below shows the circuitry of the log converted to generate an exponential output from a linear input.The emitter of Q2 in proportion to the input voltage is driven by amplifier A1 in conjunction with transistor Q1. The collector current …[Read More]
Fast Logarithmic Amplifier
This is Fast Logarithmic Amplifier circuit. Dynamic range of This circuit has is 80 dB. This circuit is configured to optimize speed rather than dynamic range. To allow the use of feed forward compensation1 on an LM101A operational amplifier, this circuit uses Transistor Q1 that is connected with diode. This compensation can increase the slew …[Read More]
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