Lighthouse Electric Small Circuits Page


Simple Transistor Circuits For Experimenting, Fun and Education

Collection of practical and fun to build small electronic circuit.
These circuits contain 1 to 4 transistors and few other componets.
Most of the parts can be found in one's junk-box or bought at the local Radio-Shack store.
They can be assembled in short time, even by a beginner.

All circuits use general purpose NPN and PNP transistors, 2N3904 for NPN; 2N3906 for PNP unless noted otherwise.

TC001: Two transistor oscillator. Changing the value of R1/R2 and C1/C2 will change the output frequency.

TC002: Pocket Metronome. Control takt speed with P1. Replace 2N1613 with any 1 Amp npn transistor.

TC003: Broadband Cable RF-Amplifier 0.5-150Mhz. Input and Output is for 75 Ohm Cable Impedance. Use ceramic capacitors and metal film resistors.

TC004: Low Noise pre-amp. 20 Hz-200 kHz (-1dB) frequency responce. Lower input impedance with R1 resistor. Output impedance is 1k.

TC005: Variable Zener Diode. Adjust the Zener voltage with P1. This circuit is especially usefull for voltages between 1 and 3 Volts.

TC006: Simple Vibrato. Adjust the frequency with P1 and gain with P2.

TC007: Temperature Control. NTC resistor senses the temperature.Relais contacts switch power on-off. Temp adjustment with P1.

TC008: Noise Generator.

TC009: Slave flash trigger switch. RadioShack LDR resistor PN may be used.

TC010: Passiv Tone Control circuit, 20Hz-100kHz frequency response.

TC011: Steam Boat Horn. To connect to an amplifier, eliminate T3 and connect as shown. Experiment with diff. caps to achieve different sound. Both caps must have same value.

TC012: Variable Capacitance. 1:5000 variation is possible. Substituting the 10k pot. with NTC or VDR resistor, a temp. or voltage dependend capacitance is created. The possibilities are nearly unlimited.

TC013:Component and Circuit Tester



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