HEWLETT PACKARD (HP) 202A
Manual de Servicio

Sect. I1 Page 2 2) Set the RANGE and FREQUENCY controls for the desired frequency. The frequency dial scale must be multiplied by the multiplying factor indicated by the RANGE switch setting to obtain the oscillator frequency. Example: 4 (on dial scale) x . l (multiplying factor indicated by RANGE switch setting) = . 4 cycles/sec.
3) Set the FUNCTION switch for the desired output waveform.

must be connected to one of the OUTPUT terminals, and the strapped pair will then be the ground side of the output.

2-6

BALANCED OUTPUT

4) Connect the equipment under test to the OUTPUT terminals.

5) Adjust the AMPLITUDE Control for the desired output voltage. Because the frequency response is rated k0.2 db, the output amplitude may be measured at any convenient frequency and the output level will be correct (within these limits) for any other frequency. NOTES When small output voltages a r e required it may be desirable to use an external attenuator. This is because the hum and noise in the output is nearly constant with output amplitude.

Connect the two OUTPUT binding posts to the equipment being supplied. The "G" binding post may then be connected to the chassis of the equipment being driven. Under these conditions the internal impedance of the Model 202A from either OUTPUT terminal to ground is 7900 ohms in series with a 1 pf capacitor (C29). A maximum dc voltage of 400 volts may be applied between either OUTPUT terminal and the "G" terminal without damaging the 1 pf capacitor (C29). The 40 ohms internal impedance (resistive) will shunt the impedance existing between the two signal inputs of the system being driven. Under circumstances where the connection places the Model 202A in series with a path carrying current, distortion of the Model 202A output will occur if greater than 10 ma peak current is caused to flow through the Model 202A output system.

@

0
EQUIPMENT SUPPLIED ground o r no signal point

To minimize distortion in the output waveform,
always use the lowest RANGE when the overlap of the FREQUENCY dial p e r m i t s a choice.

-------------

2-5
SINGLE-ENDED OUTPUT

Figure 2-2.

Balanced Output Connections

The terminal marked "(3" is isolated from the actual OUTPVT terminals. For single-ended operation "(3'

2-7

SYNC. OUT

0 EQUIPMENT BEING SUPPLIED

RO

FYgwe 2-L

Single-Ended Output C o ~ e c t i o n s

The SYNC. OUT is a negative pulse of l e s s than 5 microseconds duration and at least 10 volts peak into a 2,500 ohm load. It occurs on one of the sine and triangular c r e s t s and a t the rise o r f a l l of t h e squarewave. It occurs a t the positive c r e s t s with respect to one of the OUTPUT terminals and at the negative c r e s t of the other. Therefore, it can be changed by 180" with respect to the output system by reversing connections to the two OUTPUT terminals, which are otherwise completely interchangeable. The SYNC. OUT terminal marked "G1' is directly connected to the chassis.