Basic Electronic Circuits

Special resistors

  • Temperature-dependent resistor NTC

  • Light-dependent resistor LDR (photoresistor)

  • Light controlled relay


  • Characteristic of a diode

  • Half-wave rectification

  • Full-wave rectification

  • Measuring peak voltages, voltage doubling

  • Light emitting diodes

  • Polarity tester with diodes

  • Series connection of diodes

  • Characteristic of a Z-diode

  • Overload protection using a Z diode


  • Diode paths with transistors, testing circuit with light emitting diodes

  • Transfer characteristic of a transistor

  • Transistor circuit I: voltage control

  • Base voltage division

  • Transistor circuit II: current control

  • Light controlled transistor I: light barrier

  • Light controlled transistor II: twilight switch

  • Delay switch

  • Testing for hum

Transistor Applications

Diode circuits

  • Zero-point suppression with a Z-diode

  • Using diodes to protect against overvoltage and reverse polarity

  • Suppressing induction voltages with a diode (free-wheeling diode)

  • Smoothing pulsating DC voltages with capacitors

  • Constant current source - charging capacitors with a constant current

Voltage stabilizer circuit

  • Series voltage regulation

  • Voltage stabilizer circuit

  • Basic experiments with flip-flops

  • Bistable flip-flop as a memory element

  • Monostable flip-flop as a time-delay swich

  • Astable flip-flop (astable multivibrator)

  • Generating sounds with an astable multivibrator (police siren, birdsong)

  • Miniature organ I - musical scale on a pencil line Extra experiment: miniature organ II - making and tuning a small electronic keyboard

Amplifying circuits

  • Amplifying a voltage pulse

  • Setting and stabilizing the working-point of a single-stage microphone amplifier

  • Two-stage microphone amplifier

  • Medium-wave receiver, single-stage and two-stage

  • Basic experiment: amplifier for voltage differential (difference amplifier)

  • Sensitive light meter with a difference amplifier

  • Determining the DC voltage gain (push-pull gain) of a difference ampifier

  • Touch-contact switch, moisture and filling-level indicator

  • Current gain factors

Feedback and oscillators

  • Electronic motor

  • Acoustic feedback

  • Meissner circuit

  • Three-point oscillator

  • Phase shift oscillator

  • Wien oscillator

Opto Electronics

Experiments with light waveguides

  • Demonstration light conduction in light waveguides

  • Attenuation in the light waveguide

Light emitting diodes

  • The light emitting diode in the circuit: reverse bias and forward bias behavior

  • Characteristics of light emitting diodes

Voltage stabilizer circuit

  • Basic circuit with a photodiode

Solar cells

  • Forward and reverse direction of a solar cell

  • Internal resistance of a solar cell

  • Output and power characteristics of a solar cell

  • No-load voltage of a solar cell

  • Short-circuit current of a solar cell

  • Connecting solar cells in series

  • Connecting solar cells in parallel

  • Conversion light energy into motion


  • Photo transistor with base connection, basic experiments

  • Photo transistor equivalent circuit

  • Current gain of the photo transistor

Forked light barrier

  • Forked light barrier with following transistor

Light transmitters and receivers

  • Transmitting sound with the light waveguide

  • Transmitting music and speech with the light waveguide


Excellent Technology Co.
Hong Kong: Tel. (852) 2691 3821    Fax. (852) 2900 2980

China: Tel. (86) 150 1799 2655   Fax. (86) 755 3360 9662