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ONE, TWO OR THREE TRANSISTOR CIRCUITS FOR 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, 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:
DIY Engine Tach-Adapter with Digital Display.
This pulse shaping circuit provides at the output a DC voltage proportional to the engine speed. A panel DVM can be attached for RPM display. Calibrate with generator or 12VAC 60HZ, 4cyl=1800 RPM; 6cyl=1200RPM. The formula is: RPM=(120/cyl n) * freq
TC014:
DIY Engine Tach-Adapter for electronic ignition systems.
This circuit works with point-less electronic ignition systems. Make a 10 turn sensing-coil with solid ( 24-18Ga) insulated wire around the HV cable connecting the ignition coil and distributor. Start with one end of the wire. Secure with tape. The other end connects to the adapter. If there are more than one ignition coil, repeat each coil for each ignition coil. Connect all sensing coils at the input. Adjust sensitivity with the input trim-pot. Experiment with P1 and R6 for best results. The display can be mechanical or digital. Calibrate as in TC013
| THESE PROJECTS ARE PROVIDED 'AS-IS', WITH NO WARRANTY OF
ANY KIND. USE OF THESE CIRCUITS SHALL BE ENTIRELY AT THE USER'S OWN RISK. |
